P-dog's blog: boring but important

Physics quiz question: time for light to travel a centimeter

2012-02-14T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

How long does it take light to travel 1 inch (2.54 cm) in vacuum?
(A) 8.47×10^–11 s.
(B) 1.18×10^–10 s.
(C) 1.31×10^–7 s.
(D) 7.62×10^–6 s.

Correct answer: (C)

The speed of light in vacuum is c = 3.00×10⁸ m/s, and the relation between speed, distance, and elapsed time is:

c = ∆x/∆t,

such that solving for time gives:

∆t = (∆x)/c = (3.00×10⁸ m/s)/(1×10^-2 m) = 8.47×10^–11 s.

Response (B) is c/∆x (with a sign error in the exponent); response (C) is 1/(c*∆x); and response (D) is c*∆x (with a sign error in the exponent).

Section 30882
Exam code: quiz01pL2r
(A) : 17 students
(B) : 10 students
(C) : 1 student
(D) : 1 student

Success level: 59%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.83

Physics quiz question: frequency of light, in different media

2012-02-13T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 22.19(b)

Red laser light of wavelength 633 nm in air passes either into man-made fused quartz (index of refraction 1.459), or into natural crystalline quartz (index of refraction 1.544). In which material would the red laser light have the higher frequency?
(A) Fused quartz.
(B) Crystalline quartz.
(C) (There is a tie.)
(D) (Not enough information given.)

Correct answer: (C)

Frequency f depends on the properties of the source, and is independent of the properties of the medium (i.e., different speeds due to different indices of refraction).

Section 30882
Exam code: quiz01pL2r
(A) : 4 students
(B) : 3 students
(C) : 21 students
(D) : 0 students

Success level: 72%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.50

Physics quiz question: polarized light through different polarizers

2012-02-12T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 22.45

Polarized light is incident on two ideal polarizers. Which ideal polarizer has more light transmitted through it?
(A) Polarizer 1.
(B) Polarizer 2.
(C) (Both polarizers will have the same non-zero amount of light transmitted through them.)
(D) (Both polarizers will have no light transmitted through them.)

Correct answer: (A)

From Malus' law, the fraction of light passing through polarizer 1 is given by cos²(30°) = 0.75, while the fraction of light passing through polarizer 2 is cos ²(30°) = 0.25.

Section 30882
Exam code: quiz01pL2r
(A) : 25 students
(B) : 2 students
(C) : 2 students
(D) : 0 students

Success level: 86%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33

Physics quiz question: polarization by scattering

2012-02-11T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 22.6

If the sun is directly overhead, and you are looking at the east horizon, you would observe light that is:
(A) partially polarized horizontally, north-south.
(B) partially polarized horizontally, east-west.
(C) partially polarized vertically (up-down).
(D) randomly polarized (unpolarized).

Correct answer: (A)

Unpolarized light from overhead sun, intercepted by particle along the east horizon, makes particle vibrate north-south and east-west. From your viewpoint, you would only see the north-south polarization mode, as the east-west mode would be longitudinal (which light waves are not).

Section 30882
Exam code: quiz01pL2r
(A) : 26 students
(B) : 2 students
(C) : 0 students
(D) : 1 student

Success level: 90%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33

Physics quiz question: reception from dipole antenna transmitter

2012-02-10T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 22.1

A radio station is located due south of your location. It uses an electric dipole antenna oriented north-south. In order to maximize reception of this broadcast at your location, you need to orient an electric dipole receiving antenna:
(A) vertically.
(B) horizontally north-south.
(C) horizontally east-west.
(D) (No reception is possible using an electric dipole antenna.)

Correct answer: (D)

This electric dipole antenna will broadcast radio signals in directions perpendicular to its orientation, and none alone its ends. Since the antenna is oriented north-south and located south of the receiving antenna, no signal will be received.

Section 30882
Exam code: quiz01pL2r
(A) : 2 students
(B) : 2 students
(C) : 4 students
(D) : 21 students

Success level: 72%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.83

Physics quiz question: incident angle less than critical angle

2012-02-09T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 23.11

A beam of light strikes the interface between flint glass and air with an incident angle equal to the critical angle of 35.9°, such that the beam undergoes total internal reflection. (Drawing is not to scale.) If the incident angle of the beam of light in flint glass is decreased slightly from 35.9° to 35.8°, the incident beam would be:
(A) reflected back into flint glass.
(B) transmitted into air.
(C) (Both choices (A) and (B).)
(D) (Not enough information is given.)

Correct answer: (C)

If the incident angle in flint glass is less than the critical angle, then light will be transmitted out into the air, as well as partially reflected back into the flint glass.

Section 30882
Exam code: quiz01pL2r
(A) : 9 students
(B) : 3 students
(C) : 17 students
(D) : 0 students

Success level: 59%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

Physics quiz archive: electromagnetic waves, reflection/refraction

2012-02-08T00:05:00.000-08:00

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30882, version 1
Exam code: quiz01pL2r
Section 30882 results
Quiz 1 results (max score = 30):

0- 6 :
7-12 :	** [low = 9]
13-18 :	**********
19-24 :	***** [mean = 22.4 +/- 6.5]
25-30 :	************ [high = 30]

Astronomy current events question: Fobos-Grunt mission objective

2012-02-07T09:44:00.000-08:00

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

Jonathan Amos, "Phobos-Grunt: Failed Probe 'Falls Over Pacific,'" January 15, 2012
http://www.bbc.co.uk/news/science-environment-16491457

The Russian Space Agency Fobos-Grunt ("Phobos-Ground") spacecraft, which crash-landed into the Pacific, was intended to travel to Mars to:
(A) bring back a sample from one of its moons.
(B) burrow underground to search for water.
(C) produce fuel for future space missions.
(D) search for the defunct NASA Spirit rover.
(E) map the "face on Mars" with high-resolution radar.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 31 students
(B) : 8 students
(C) : 1 student
(D) : 2 students
(E) : 14 students

Astronomy current events question: Opportunity rover charging batteries

2012-02-07T09:41:00.000-08:00

Kelly Beatty, "Opportunity Takes a Bow, Gets Some Rest," January 25, 2012
http://www.skyandtelescope.com/news/home/Opportunity-Takes-Bow-Gets-Rest-138098593.html

The NASA Mars Exploration Rover Opportunity will park for the next several months, to:
(A) charge batteries during Martian winter.
(B) listen for Mars microquakes.
(C) upgrade and reboot its operating software.
(D) wait for the quicksand around it to harden.
(E) avoid exposure to solar flares.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 18 students
(B) : 6 students
(C) : 1 student
(D) : 0 students
(E) : 2 students

Astronomy current events question: subsurface ice on Vesta?

2012-02-07T09:27:00.000-08:00

Elizabeth Zubritsky and Jia-Rui Cook, "Vesta Likely Cold and Dark Enough for Ice," January 25, 2012
http://www.nasa.gov/mission_pages/dawn/news/dawn20120125.html

The asteroid Vesta may contain ice just below its surface, according to models based on:
(A) Antarctic glaciers.
(B) a Russian space probe drilling into its crust.
(C) meteorite samples containing Vesta material.
(D) Hubble Space Telescope observations.
(E) icy vapor trails.

Correct answer: (D)

Student responses
Sections 30678, 30679, 30680
(A) : 4 students
(B) : 2 students
(C) : 7 students
(D) : 15 students
(E) : 0 students

Astronomy current events question: "Meteorito" wine

2012-02-07T09:24:00.000-08:00

Lauren Davis, "Hate Earthy Wines? Try One Made from Meteorites," January 21, 2012
http://io9.com/5878095/hate-earthy-wines-try-one-made-from-meteorites

"Meteorito" is a new Chilean wine for sale:
(A) made from grapes grown in the soil of an ancient impact crater.
(B) infused with a meteorite fragment.
(C) approved by International Space Station astronauts.
(D) from the La Silla Paranal Observatory vineyard.
(E) based on a popular Chilean science-fiction movie.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 10 students
(B) : 36 students
(C) : 2 students
(D) : 8 students
(E) : 0 students

Astronomy quiz question: Ursa Major/Cassiopeia position

2012-02-06T00:05:00.000-08:00

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
Consider the view of the northern horizon shown below, as seen by an observer on February 2 in San Luis Obispo, CA. Ignore daylight saving time. Assume you can see stars in daylight. What time is this?
(A) 10:00 AM.
(B) 12:00 PM.
(C) 2:00 PM.
(D) 9:00 PM.

Correct answer: (A)

Response (B) corresponds to the sky on January 1; response (C) has Ursa Major at its lowest point in the sky on February 2; and response (D) has Ursa Major to the right (east) of Polaris on February 2.

Section 30674
Exam code: quiz01n3Wb
(A) : 27 students
(B) : 1 student
(C) : 0 students
(D) : 4 students
(No response : 1 student)

Success level: 79% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

[Version 2]
Consider the view of the northern horizon shown below, as seen by an observer on February 2 in San Luis Obispo, CA. Ignore daylight saving time. Assume you can see stars in daylight. What time is this?
(A) 5:00 AM.
(B) 10:00 AM.
(C) 12:00 PM.
(D) 9:00 PM.

Correct answer: (B)

Response (A) has Cassiopeia at its lowest point in the sky on February 2; response (C) corresponds to the sky on January 1; and response (D) has Cassiopeia to the left (west) of Polaris on February 2.

Section 30676
Exam code: quiz01sH0p
(A) : 1 student
(B) : 39 students
(C) : 2 students
(D) : 6 students

Success level: 83% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.46

Astronomy quiz question: time to change moon phases

2012-02-05T00:05:00.000-08:00

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
Approximately how much time elapses between first quarter to full moon?
(A) An hour.
(B) Several hours.
(C) 12 hours.
(D) 24 hours.
(E) Several days.
(F) One week.
(G) Several weeks.
(H) 28 days.

Correct answer: (F)

The moon will take approximately four weeks to go through all eight of its phases, such that it will take approximately one week to go through two phases (starting from first quarter, to go through waxing gibbous, to end at full moon).

Section 30674
Exam code: quiz01n3Wb
(A) : 0 students
(B) : 1 student
(C) : 0 students
(D) : 0 students
(E) : 2 students
(F) : 26 students
(G) : 4 students
(H) : 1 student
(No response : 1 student)

Success level: 77% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

[Version 2]
Approximately how much time elapses between full moon to third quarter?
(A) An hour.
(B) Several hours.
(C) 12 hours.
(D) 24 hours.
(E) Several days.
(F) One week.
(G) Several weeks.
(H) 28 days.

Correct answer: (F)

Section 30676
Exam code: quiz01sH0p
(A) : 0 students
(B) : 0 students
(C) : 0 students
(D) : 0 students
(E) : 3 students
(F) : 35 students
(G) : 8 students
(H): 2 students

Success level: 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.62

Astronomy quiz question: moon phase, overhead to setting?

2012-02-04T00:05:00.000-08:00

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
The waning gibbous moon is directly overhead at 3:00 AM. What phase will the moon have when it sets? Clearly circle your answer below.

Correct answer: (G) (Waning gibbous.)

The moon will take approximately four weeks to go through all eight of its phases, such that it will take approximately one week to go through two phases, or approximately half of a week to go to the next consecutive phase. As the moon takes approximately 12 hours from moonrise to moonset, the phase it has while overhead will be the same phase as it sets six hours later.

Section 30674
Exam code: quiz01n3Wb
(A) : 2 students
(B) : 0 students
(C) : 4 students
(D) : 1 student
(E) : 12 students
(F) : 1 student
(G) : 15 students
(H) : 0 students

Success level: 46% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.56

[Version 2]
The waxing gibbous moon is directly overhead at 9:00 PM. What phase will the moon have when it sets? Clearly circle your answer below.

Correct answer: (A) (Waning gibbous.)

Section 30676
Exam code: quiz01sH0p
(A) : 26 students
(B) : 3 students
(C) : 6 students
(D) : 0 students
(E) : 3 students
(F) : 1 student
(G) : 6 students
(H): 0 students
(No response : 3 students

Success level: 57% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.48

Astronomy quiz archive: stars/sun/seasons/moon phases

2012-02-03T00:05:00.000-08:00

Astronomy 210 Quiz 1, fall semester 2012
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz01n3Wb
Section 30674

0- 8.0 :	** [low = 7.0]
8.5-16.0 :	***
16.5-24.0 :	************
24.5-32.0 :	*********** [mean = 24.7 +/- 7.9]
32.5-40.0 :	******* [high = 40.0]

Section 30676, version 1
Exam code: quiz01sH0p

Section 30676** [low = 7.5]

0- 8.0 :
8.5-16.0 :	*******
16.5-24.0 :	***********
24.5-32.0 :	**************** [mean = 25.4 +/- 9.0]
32.5-40.0 :	************ [high = 40.0]

Astronomy quiz question: sun-zodiac timing

2012-02-02T00:05:00.000-08:00

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

If the sun is in front of a certain zodiac constellation today, it will take approximately __________ to be in front of the next zodiac constellation.
(A) an hour.
(B) 12 hours.
(C) 24 hours.
(D) one month.
(E) one year.
(F) 26,000 years.

Correct answer: (D).

With one year for Earth to complete one revolution around the sun, and 12 zodiac constellations approximately evenly spaced along the ecliptic, then the sun will take about one month to traverse each zodiac constellation.

Section 30674
Exam code: quiz01n3Wb
(A) : 1 student
(B) : students
(C) : 0 students
(D) : 32 students
(E) : 0 students
(F) : 1 student
(No response: 1 student)

Success level: 92% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

Section 30676
Exam code: quiz01sH0p
(A) : 1 student
(B) : 0 students
(C) : 2 students
(D) : 38 students
(E) : 4 students
(F) : 2 students

Success level: 80% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.31

Astronomy current events question: NASA Dawn mission at Vesta

2012-01-30T19:05:00.000-08:00

Jia-Rui Cook, "Dawn Obtains First Low Altitude Images of Vesta," December 21, 2011
http://www.nasa.gov/mission_pages/dawn/news/dawn20111221.html

NASA's Dawn spacecraft is currently making low-altitude maps of:
(A) Vesta, an asteroid.
(B) Saturn's rings.
(C) Halley's comet.
(D) sunspots and solar flares.
(E) meteorite damage at the International Space Station.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 36 students
(B) : 9 students
(C) : 1 student
(D) : 15 students
(E) : 2 students

Astronomy current events question: distant galaxy GN-108036

2012-01-30T19:02:00.000-08:00

Whitney Clavin, "NASA Telescopes Help Find Rare Galaxy at Dawn of Time," December 21, 2011
http://www.nasa.gov/mission_pages/spitzer/news/spitzer20111221.html

NASA's Spitzer and Hubble space telescopes measured the unusual __________ of galaxy GN-108036, one of the most distant galaxies discovered.
(A) antimatter to matter ratio.
(B) amount of dark matter.
(C) star production rate.
(D) supermassive central black hole.
(E) blueshift.

Correct answer: (C)

Student responses
Sections 30678, 30679, 30680
(A) : 9 students
(B) : 10 students
(C) : 34 students
(D) : 4 students
(E) : 4 students

Astronomy current events question: confirming Kepler space telescope discoveries

2012-01-30T16:59:00.000-08:00

Alan MacRobert, "Kepler Team Confirms Two Hot Earths," December 20, 2011
http://www.skyandtelescope.com/news/Kepler-Team-Confirms-Two-Hot-Earths-Hundreds-More-Await-135865388.html

__________ is used to confirm planets discovered by NASA's Kepler space telescope.
(A) Radar pulse reflections.
(B) Star wobbles detected by ground-based telescopes.
(C) Follow-up reports by amateur astronomers.
(D) Visual observations by the Hubble space telescope.
(E) Detection of the presence of an atmosphere.

Correct answer: (B)

Student responses
Sections 30678, 30679, 30680
(A) : 12 students
(B) : 11 students
(C) : 0 students
(D) : 5 students
(E) : 3 students

Astronomy current events question: KIC 05807616 planets

2012-01-30T16:53:00.000-08:00

Astronomy.com editors, "Astronomers Discover Two Planets That Survived Their Star's Expansion," December 22, 2011
http://astronomy.com/en/News-Observing/News/2011/12/Astronomers%20discover%20two%20planets%20that%20survived%20their%20stars%20expansion.aspx

Two planets that apparently survived being engulfed by their bloated, dying parent star KIC 05807616 were discovered by NASA's Kepler space telescope from:
(A) light reflected or emitted by the planets.
(B) radar pulse timing variations.
(C) star wobbles detected by ground-based telescopes.
(D) asteroid fragment trails.
(E) reformation of their cores.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 18 students
(B) : 5 students
(C) : 2 students
(D) : 4 students
(E) : 3 students

Overheard: not full moon is not full

2012-01-29T12:27:00.000-08:00

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

(Overheard during presentation introducing moon phases, showing a slide of a nearly full moon.)

Instructor: "So, which phase is this?"

Students: "Waxing gibbous?"

Instructor: (Beat.) "Are you sure? How do you know that this is not a full moon?"

Student: (Beat.) "Because it's not full?"

Astronomy in-class activity: first-day student expectations, questions

2012-01-21T09:59:00.000-08:00

Astronomy 210 In-class activity 1, spring semester 2011
Cuesta College, San Luis Obispo, CA

120121-interestingwordle
http://www.wordle.net/show/wrdl/4706913/Untitled
Originally uploaded by Waifer X

Wordle.net tag cloud for potentially interesting astronomy topics, generated by students on the first day of class (http://www.wordle.net/show/wrdl/3935554/Untitled).

120121-confusingwordle
http://www.flickr.com/photos/waiferx/6737065165/
Originally uploaded by Waifer X

Wordle.net tag cloud for potentially confusing astronomy topics, generated by students on the first day of class (http://www.wordle.net/show/wrdl/4706918/Untitled).

On the first day of class, students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet to discuss concepts that will potentially be interesting or confusing to them later in the semester. Students are also encouraged to write down a comment or a question for the instructor to go over during the whole-class discussion, after the in-class activity worksheets are turned in.

[Responses have been edited to consolidate common related subjects.]

Discuss in your group astronomy-related concepts you expect to be interesting or confusing later in this course. Use one word or short phrases (e.g., "Pluto," "black holes," "beginning of time") for each concept.

List at least three astronomy-related concepts you expect to be interesting.

Student responses
Sections 30674, 30676

exoplanets, sun, light
blackholes, planetatmospheres, constellations
bigbang, life, light
moons, galaxies, constellations, blackholes, life
constellations, blackholes, supernovae
time, rotations
bigbang, astrology, galaxies
light, blackholes, cosmology
planets, constellations, lightyear
blackholes, bigbang, supernovae
light, galaxies, water
names, blackholes, bigbang
constellations, quarks, tides, blackholes
universe, blackholes, stars
aliens, blackholes, stars, solarflares, northernlights, asteroidimpacts
stars, aliens, blackholes, darkmatter
planets, Mars, atmospheres
Pluto, aliens, galaxies, light
planets, exploration, timetravel, stardeath
universe, sun, Pluto
supernovae, gravity, solarflares, eclipses, meteorshowers
blackholes, aliens, constellations
blackholes, galaxies, darkmatter, lightyear
constellations, blackholes, bigbang, gravity
universe, bigbang, time
blackholes, bigbang, solarflares

List at least three astronomy-related concepts you expect to be confusing.

Student responses
Sections 30674, 30676

blackholes, constellations, bigbang
time, distances, blackholes
bigbang, universe, gravity
blackholes, bigbang, universe
darkmatter, galaxies, blackholes
light, bigbang, starformation
constellations, blackholes, rings
planets, everything, starformation, stardeath
galaxies, names
blackholes, blackholes, bigbang
bigbang, constellations, space
elements, constellations, space, time, light
distances, eclipses, blackholes
galaxies, math, atmosphere
physics, orbits, math
time, cosmology, space, bigbang, knowledge
physics, blackholes, light
names, physics, galaxies
bigbang, spacetime, moonphases
planets, planets, planets
planets, solarflares, blackholes, darkmatter, asteroids
universe, blackholes, moonphases
math, universe, cosmology
space-time, matter, constellations
lightyear, gravity
planets, physics, galaxies

Each week after class you will receive credit for asking a question, or making a comment that the instructor might respond to at the start of the following class (while your identity is kept anonymous). Ask at least one question, or make a comment that you would like the instructor to respond to at the end of this in-class activity.

Student responses
Sections 30674, 30676

"What do you think is the most exciting thing to learn in astronomy?"

"What tools are used to measure the distance of the known universe?"

"We've landed on the moon, we've sent telescopes deep into outer space--what do you think technology will let us or allow us to do next?"

"How many dimensions are there?"

"What makes stars go supernova?"

"How did the beginning of time happen?"

"What's your favorite planet, P-dog?"

"Why does a star combust after the gas is gone?"

"Recent study found a planet that could hold life?"

"What is your favorite constellation, and why?"

"What's most interesting to you in astronomy?"

"Currently, what is the general consensus in the science community on there being life on another planet in the universe?"

"Can we, should we, be concerned about space debris?"

"How often are we threatened by a comet or asteroid or other large astronomical disaster?"

"Am I going to need a tutor?"

"How did you become an astronomy teacher, and hired to do it, without actually taking an astronomy course?"

"What is the ring around Saturn made of?"

"What's responsible for creating the northern lights?"

"How would we know what a star in the sky is? It could be a solar system, or even a galaxy, right?"

"If a star is brighter, does that mean it could be closer, bigger, either of those?"

"What is Nibiru/Planet X?"

"What is the 2012 scare all about and the reason for it?"

"Do you believe in extraterrestrials?"

"How have you been known as 'P-dog?'"

"How do asteroid belts maintain structure and orbits?"

"What's the deal with Pluto?"

"Do you believe in aliens? Or life on other planets?"

"Do you believe in extraterrestrials?"

"What is your favorite planet, and why?"

"How do we know the universe is 5 billion light years?"

Astronomy in-class activity: astronomy in the marketplace tags

2012-01-20T18:19:00.001-08:00

Astronomy 210 In-class activity 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

120120-carwordle
http://www.flickr.com/photos/waiferx/6733751333/
Originally uploaded by Waifer X

Wordle.net tag cloud for astronomy-related car brand names, generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/4705552/Untitled).

120120-foodwordle
http://www.flickr.com/photos/waiferx/6733751421/
Originally uploaded by Waifer X

Wordle.net tag cloud for astronomy-related food brand names available in a supermarket, generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/4705559/Untitled).

120120-nonfoodwordle
http://www.flickr.com/photos/waiferx/6733751513/
Originally uploaded by Waifer X

Wordle.net tag cloud for astronomy-related non-food brand names available in a supermarket, generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/4705569/Untitled).

Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet to discuss car brand names, and food and non-food brand names found in supermarkets (adapted from D. Schatz, "Why Should We Care About Exploding Stars?" Universe in the Classroom, no. 8, Spring 1987 (http://www.astrosociety.org/education/publications/tnl/08/stars2.html).

There are many astronomy-related brand names. Consider car brand names (old and new); and brand names for food and non-food items that are typically found in the supermarket. Do not consider titles of TV shows, movies, or books.

List at least three astronomy-related car brand names.

Student responses
Sections 30674, 30676

Saturn, Mercury, Titan
Saturn, Mercury, Astro
Infiniti, Mercury, Saturn
Saturn, Mercury, Subaru, Volt, Sky, Celeste
Mercury, Subaru, Eclipse
Taurus, Saturn, Mercury
Saturn, Mercury, Subaru, Astro
Saturn, Infiniti, Nova
Saturn, Subaru, Volt
Nova, Saturn, Galaxy
Astro, Galaxy, Taurus
Saturn, Infiniti, Mercury
Mercury, Saturn, Taurus
Mercury, Saturn, Infiniti
Aerostar, Explorer, Saturn, Aura, Mercury
Mercury, Eclipse, Saturn
Mercury, Saturn, Comet
Saturn, Eclipse, Scion, Astro
Saturn, Mercury, Taurus, Eclipse, Nova, Voyager
Saturn, Mercury, Galaxy
Nova, Saturn, Mercury, Astro
Saturn, Mercury, Fusion
Mercury, Cobalt, Nova, Astro, Saturn
Mercury, Saturn, Taurus, Subaru, Galaxy
Saturn, Nova, Mercury, Galaxy, Astro
Mercury, Saturn, Comet

List at least three astronomy-related food brand names typically found in the supermarket.

Student responses
Sections 30674, 30676

MoonPie, MilkyWay
starfruit, Starburst, MilkyWay, Marsbar
MilkyWay, Starburst, Orbit
Starburst, MilkyWay, LuckyCharms
Marsbar, MilkyWay, Starburst
MilkyWay, Starburst, StaroftheSea
Sunkist, SunChips, Starburst
MoonPie, MilkyWay, Sunkist
Starburst, MilkyWay, SunChips
MilkyWay, MoonPie, Marsbar, SunChips
Sunkist, Starburst, MilkyWay
MilkyWay, Marsbar, MoonPie
MilkyWay, MoonPie, Orbit
Starburst, Marsbar, MilkyWay
CapriSun, Sunkist, SunnyD
MilkyWay, Starburst, Eclipse, Marsbar
Sunburst, MilkyWay, Starburst, starfruit
MoonPie, MilkyWay, Lunabar
Marbar, MilkyWay, Moonshine, Starbucks, BlueMoon
MilkyWay, Starburst, Marsbar
AstroPop, SunnyD, MilkyWay
MilkyWay, MoonPie, Marsbar
BlueMoon, MilkyWay, Sunkist, SunnyD, Starburst
Trident, Orbit, AstroPop, MilkyWay, Starburst
MilkyWay, starfruit, Marsbar
MilkyWay, Marsbar, Corona, Sunkist, SunnyD, BlueMoon

List at least three astronomy-related non-food brand names typically found in the supermarket.

Student responses
Sections 30674, 30676

BlueMoon
Venusrazor, Comet, BlueMoon
Starbucks, light, gravity
BlueMoon, Skyline, Comet
Venusrazor, Orbit
Comet, Venusrazor
Sextantwine, Venusrazor, Comet
SkyyVodka, BlueMoon, VerizonGalaxy
Skyviewwine, sunscreen
BlueMoon, Sunkist, Starburst
Comet, Moonshine, Ka-boom
Comet, Orbit, Venusrazor
Comet, BlueMoon, Tide
sunscreen, Tide, PopularScience
Sun, Comet, Dawn
Venusrazor, BlueMoon, Comet
Comet, sunscreen, Dawn
Nova, SunnyD, Starbucks
Comet, tequilasunrise, LAGalaxy, Globetrotters, Venusrazor
sunglasses, Venusrazor, SpaceBags
Comet, BlueMoon, Nova
BlueMoon, Telescopicmascara, Comet
Comet, SpaceBags, Venusrazor
Comet, Ajax, Venusrazor, Tide, Trojans
Comet, sunscreen, Moonshine
Comet, Tide, sunscreen

Presentation: redirecting light

2012-01-17T00:05:00.000-08:00

Now that we've already been introduced to "light," that is, the electromagnetic spectrum, let's take a look at redirecting (visible) light. Note that like presentations in the previous first semester of this college physics sequence, this presentation will hopefully give you a sense of what Bill Nye ("The Science Guy") likes to describe as "PBJ"--the "passion, beauty, and joy" of reflecting and refracting light. We simply don't have time for an exhaustive, comprehensive discussion of this material in class--that's what your textbook is for!

Reflection is redirecting light by bouncing it off of a surface.

Conventionally we consider reflections off of flat surfaces. (Don't worry about what's about to happen here--it's art!)

Even with reflections off of curved surfaces, each point on it can be considered a locally flat surface.

And more "PBJ" for reflections--they have the curious property of converting love into hate, or is it the other way around?

The law of reflection is simple geometry--for a (visible) ray of light incident on a flat surface, if we measure the angle of incident with respect to the normal (a line drawn perpendicular to the surface), the reflected ray will make the same angle as it leaves the surface. (This law also applies for curved surfaces, provided we look close enough such that it look locally flat.)

Instead of bouncing light off of surfaces, if light can pass into a transparent material, we will have refraction, where it is redirected by being "bent."

Refraction occurs when light starts in one material, and passes into another. (This art installation only gives the illusion of seeing light from people underwater; instead there is only a thin layer of water supported by sheet of glass between these two levels.)

When light does start in one medium, and pass into another medium, it will refract, or bend, which can produce curious results.

Look at the exhaust plume from this jet: heat warms the air and changes its density, making light travel at a different speed through it, and it will be bent in interesting directions. Also note the shockwaves from leading edges on the jet--here air is compressed, and again light traveling through it will be bend it in interesting directions.

Take a look at this transparent block. Light will travel with a different speed through it than through air, and so the light will be bend in interesting directions. Why can't we see the block when we pour water around it? (Video link: "100108-1140566.")

Quantitatively, "Snell's" law describes how light will bend as it passes from one medium into another medium. Note that angles for both the incident ray and refracted ray are measured with respect to the normal (that imaginary line drawn perpendicular to the interface between the two media). The medium with the lower index of refraction will have the larger angle (actually, the larger sine of that angle). (This law of refraction is commonly known as "Snell's" law, but in France it is referred to a "Descartes'" law, as René Descartes is French, while Willbrord Snellius is Dutch.)

Since the index of refraction is a measure of the "optical slowness" of a material, a faster speed of light corresponds to a lower index of refraction, and a larger angle, as it travels into a material with a slower speed, a higher index of refraction, and a smaller angle. Mnemonic: "Fast-to-slow, bend towards the normal."

Consider starting in a medium with a greater index of refraction. Note that angles for both the incident ray and refracted ray are still measured with respect to the normal (that imaginary line drawn perpendicular to the interface between the two media). The medium with the higher index of refraction will have the smaller angle (actually, the smaller sine of that angle).

And since the index of refraction is a measure of the "optical slowness" of a material, a slower speed of light corresponds to a higher index of refraction, and a smaller angle, as it travels into a material with a faster speed, a lower index of refraction, and a larger angle. Mnemonic: "Slow-to-fast, bend away from the normal."

Presentation: electromagnetic waves

2012-01-16T09:49:00.000-08:00

We'll start off the second semester of college physics with light, or more correctly, electromagnetic waves. Since we are covering this topic after rope and string waves, but before electricity and magnetism, this will concentrate on describing their behavior in terms of one-dimensional waves rather than explaining it in terms of three-dimensional electromagnetic fields.

Consider all types of "light."

The electromagnetic spectrum encompasses all types of "light," here listed from low frequency to high frequency. Notice that visible light is only a very small portion of the entire electromagnetic spectrum, which we perceive as colors. The vast majority of the electromagnetic spectrum is invisible to our eyes, but we can detect their presence indirectly with certain instruments, or even our bodies. (When discussing all types of "light," we'll use "electromagnetic waves," as often "light" refers only to visible light.) Let's introduce these types of light...oops, electromagnetic waves, from lowest to highest frequency.

The lowest frequency form of electromagnetic waves are collectively known as radio waves, which are subdivided into microwave, TV, FM and AM bands depending on the type of device used to send and receive these forms of electromagnetic waves.

Slightly higher in frequency along the electromagnetic spectrum is infrared, also known as "heat waves," which our eyes cannot directly see (but we can indirectly feel), but certain devices allow us to "see" in the infrared. (Video link: "infrared heat cam.")

Then slightly higher in frequency on the electromagnetic spectrum is visible light, the only type of "light" we can directly see with our eyes. (What is this eye looking at?)

Higher in frequency on the electromagnetic spectrum, we're back again to types of "light" we cannot directly see with our eyes, but we can indirectly "see" with special devices, or in this case, materials that react in certain ways to being exposed to ultraviolet, such as our skin, or this Milky Way(R) candy bar.

"Who was Count Dooku's Jedi Mentor?"

So either children are supposed be Star Wars trivia experts, or have to go to a nightclub with "blacklights" in order to answer this correctly...

Higher in frequency is x-rays, which again cannot be seen by our eyes (well, maybe for Superman), but can be made visible with special devices or certain materials. Note that tissue is relatively transparent to x-rays, while bone, and especially metals are opaque. (What is that thing in this person's nose?)

And highest in frequency are gamma rays, which have higher penetration than x-rays, allowing inspection inside metal shipping containers.

Now let's look at the parameters used to describe these forms of "light," and the connections between them. (From here on, since we'll be discussing the transmission of visible light through different types of transparent media, we'll drop the quotation marks around "light.")

(This is a review of a previous discussion of one-dimensional rope and string waves from last semester.) Note the hierarchy of these wave parameters. Since the wave speed is determined by properties of the material it travels through (independent of the source), and the frequency is determined by the source (independent of the medium), these are said to be independent wave parameters. In contrast, the wavelength of the wave is dependent on both the independent speed and frequency parameters. Algebraically there is nothing wrong with expressing this relation as v = λf and f = v/λ, as long as you recognize that the dependency of λ doesn't change.

This is a cartoon model of how the independent and dependent parameters remain constant, or change. Consider light passing from a medium where it has a fast speed, into a different medium where it has a slow speed. The frequency of this light does not change (which depends on its source), so ideally it is still visible light, and hasn't changed frequency to become some other type of electromagnetic waves such as radio or gamma rays! Since the frequency (and type of light) is unchanged, but the speed does change (due to the change in medium), then the wavelength changes, here decreasing ("scrunching") due to the decrease in speed in the new medium.

(N.b.: we are ignoring dispersion for the purposes of this discussion.)

Light changes speed (and wavelength) as it travels through different materials. Commonly used instead of the speed of light through different materials is the "index of refraction."

The index of refraction is defined as the ratio of speed of light in vacuum (c = 3.00x10⁸ m/s) to the actual speed of light in that material. Thus for vacuum, n = 1, while for all other materials, light will travel slower, such that n > 1, and the index of refraction can be considered a measure of "optical slowness" of a material.

Light will travel quickest through vacuum, and the index of refraction is 1.

Through air, light will travel very slightly slower than it does through vacuum, so the index of refraction for air is slightly greater than 1, but to three or fewer significant figures, n can be approximated as 1.

Light will travel noticeably slower through ice, so the index of refraction for ice is noticeably greater than 1.

Light travels a bit slower through water, and so the index of refraction for water is slightly greater than for ice.

Light typically travels slower through glass than through water, so again, a greater index of refraction for glass than water. (Note that different types of glass will have slightly different indices of refraction.)

At the extreme is light traveling through diamond, which for our purposes has the greatest "optical slowness," and the greatest possible index of refraction.

Astronomy haiku: dark matter

2011-12-30T09:14:00.000-08:00

Astronomy 210 Haiku review, fall semester 2011
Cuesta College, San Luis Obispo, CA

Students find their assigned groups of three to four students, and work cooperatively on an worksheet to review for a midterm.

Identify the relevant astronomy concept/answer for this haiku. Briefly explain your choice. Partial credit possible.

Surrounding halo,
invisible gravity.
Holds Milky Way tight.
http://twitter.com/#!/Patrick_M_Len/status/72024267604234240

Concept: __________
Explanation: __________

Section 70160

"Dark matter--Evidence that extra mass lies in extended halo sometimes called dark halo. Not luminous matter detected by its gravitational force."

"Dark matter--No one has seen dark matter because it doesn't give off light, but it creates gravity, so we know it exists."

"Dark matter--Proves Kepler's third law wrong because stars farther out do not move slower because there is no center of gravity."

"Dark matter--Dark matter is gravity that holds the Milky Way together and is unable to be seen."

"Dark matter--The Milky Way doesn't follow Kepler's third law."

"Dark matter--Dark matter is invisible and it holds everything inside the Milky Way."

"Dark matter--Dark matter holds the Milky Way together."

Section 70158

"Dark matter--That's what holds the Milky Way together."

"Monolithic collapse--flattens out over time with halo making disk left."

"Dark matter--Dark matter is the unseen gravity force which fills the universe around galaxies, surrounding the Milky Way."

"Black hole! You know black holes are present when there is a gravity alteration like an entire galaxy clumped together."

"Dark matter--Dark matter is the stuff that surrounds the Milky Way and keeps everything tight."

"Black hole--Black holes are at the center of spiral galaxies and have infinite gravity due to their immense density."

"Dark matter--Dark matter surrounds galaxies, holding them together as they rotate with lots of mass."

"Antimatter/dark matter--is found all around the Milky Way and is unexplained but we know it's there."

Dark matter--Dark matter is invisible but still creates a gravitational pull."

Astronomy in-class activity: planet-hunting

2011-12-28T00:05:00.000-08:00

Astronomy 210 In-class activity 6 v.11.12.22, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet to determine where in the sky each naked-eye planet will be observed on a given date (here, February 2, 2012).

Previous posts:

Astronomy in-class activity: planet-hunting
fall semester 2011 (September 1, 2011).
Astronomy in-class activity: planet-hunting
spring semester 2011 (February 2, 2011).
Astronomy in-class activity: planet-hunting
fall semester 2010 (September 2, 2010).
Astronomy in-class activity: planet-hunting
spring semester 2010 (February 4, 2010).

Astronomy final exam question: apparent magnitudes replaced with absolute magnitudes?

2011-12-27T00:05:00.000-08:00

Astronomy 210 Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

P-dog: If the apparent magnitude of every star in our night sky were changed to its absolute magnitude value what would the night sky look like then?
tham153: The sky would be brighter, as most stars are further away than [10 parsecs]...

Discuss whether or not if this answer is correct, and how you know this. Explain using the properties of apparent magnitude, absolute magnitude, and distances to stars.

*Source: http://answers.yahoo.com/question/index;_ylt=ArPi_iM5OLjDsXxNYBK7Kj3sy6IX;_ylv=3?qid=20111121163651AAds3i5.

Solution and grading rubric:

p = 20/20:
Correct. Understands difference between apparent magnitude (m) values and absolute magnitude (M_V) values, and that stars closer or farther than 10 parsecs away will appear dimmer or brighter, respectively, if apparent magnitudes were replaced with absolute magnitude values. May argue night sky will be brighter assuming this is done to all stars in Milky Way (or universe), or may argue night sky will be dimmer assuming that this is done only to (visible?) stars in night sky.
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least understands the difference between m and M_V
values with respect to star distances, and that smaller positive (or more
negative) magnitudes are brighter.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Garbled definitions/relations
between d, m, and M_V.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:Section 70158
Exam code: finalsf4R
p: 15 students
r: 2 students
t: 2 students
v: 13 students
x: 0 students
y: 0 students
z: 1 student

Grading distribution:Section 70160
Exam code: finalN3aR
p: 16 students
r: 2 students
t: 3 students
v: 0 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 1985):
Another sample "p" response (from student 6288):
A sample "v" response (from student 8436), claiming the answer is "SWAG" (a scientific wild-a## guess):

Astronomy final exam question: why Mars inhospitable?

2011-12-26T00:05:00.000-08:00

Astronomy 210 Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

CARTART: Why is Mars [too] cold to support life?
yeah: [B]ecause [M]ars is farther from the sun.
swbarnes2: Another factor for Mars is...its small mass...

Discuss why the answers from "yeah" and "swbarnes2" both correctly answer the question from "CARTART," and how you know this. Explain using the properties of greenhouse gases and geological activity.

*Source: http://answers.yahoo.com/question/index;_ylt=As.pYTdoJvfCxjzc33mt6LQjzKIX;_ylv=3?qid=20080913120029AAeOGlQ.

Solution and grading rubric:

p = 20/20:
Correct. Discusses answers from both "yeah" and "swbarnes2." Being farther from the sun, Mars would receive less radiation for a greenhouse effect. Mars' small mass would mean less outgassing, and also be unable to retain an atmosphere sufficient for greenhouse effect.
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of two explanations is problematic/incomplete, the other is correct.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Both answers are problematic/incomplete, or one answer correct, while the other is missing.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least understands factors that contribute to atmosphere density and greenhouse effect.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Discusses factors other than relevant to the greenhouse effect.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:Section 70158
Exam code: finalsf4R
p: 13 students
r: 4 students
t: 5 students
v: 7 students
x: 3 students
y: 0 students
z: 1 student

Grading distribution:Section 70160
Exam code: finalN3aR
p: 9 students
r: 6 students
t: 5 students
v: 5 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 2286):
A sample "p" response (from student 2003):

Student scribble: "dwarf planet"

2011-12-24T00:05:00.000-08:00

Doodle by E. Winkle. Astronomy 210 Final Exam, Cuesta College, San Luis Obispo, CA.

Astronomy final exam question: Ceres not a moon because of size?

2011-12-23T00:05:00.000-08:00

Astronomy 210 Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

Atanvaryar: What do you know about Ceres and [d]warf [p]lanets?
DVOTA: Dwarf planets aren't big enough to be planets, but too big to be moons. [Because of this,] Ceres is a dwarf planet [instead of a moon].

Discuss whether or not if this answer is correct, and how you know this. Explain using the International Astronomical Union classification scheme.

*Source: http://answers.yahoo.com/question/index;_ylt=AsNsF7bYsJ7Lg_p.GeR7uMojzKIX;_ylv=3?qid=20100219202117AAPqLPe.

Solution and grading rubric:

p = 20/20:
Correct. Explicitly shows how moons and dwarf planets are mutually exclusive categories in the IAU classification scheme, or explains that Ceres could be a moon if it orbited a planet (thus it is not "too big" to be a moon), and/or that Ceres is smaller than some jovian moons.
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Discusses IAU requirements, but does not address why online comment is incorrect or unclear.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problematic/incomplete discussion of IAU classification scheme, and/or why online comment is incorrect.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least demonstrates some understanding of IAU classification scheme.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:Section 70158
Exam code: finalsf4R
p: 7 students
r: 10 students
t: 12 students
v: 3 students
x: 0 students
y: 0 students
z: 1 student

Grading distribution:Section 70160
Exam code: finalN3aR
p: 22 students
r: 0 students
t: 1 student
v: 1 student
x: 1 student
y: 1 student
z: 0 students

A sample "p" response (from student 2286):
Another sample "p" response (from student 3592):

Physics final exam question: cooling a liquid-filled glass

2011-12-22T00:05:00.000-08:00

Physics 205A Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 13.14, 13.15

A glass container is filled to the brim with a liquid when the system is at 40° C. After the system is cooled to 15° C, the liquid level is slightly below the top of the container. There are no phase changes. Which material (glass or liquid) has a larger coefficient of volume expansion? Explain your answer using the properties of temperature and thermal expansion.

Solution and grading rubric:

p = 10/10:
Correct. Argues that since liquid contracted more than the glass, then the liquid must have a greater volume expansion coefficient than the glass.
r = 8/10:
As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes.
t = 6/10:
Nearly correct, but argument has conceptual errors, or is incomplete.
v = 4/10:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
x = 2/10:
Implementation of ideas, but credit given for effort rather than merit.
y = 1/10: Irrelevant discussion/effectively blank.
y = 1/10:
Irrelevant discussion/effectively blank.
z = 0/10:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: finalB0xs
p: 37 students
r: 8 students
t: 0 students
v: 1 student
x: 1 student
y: 1 student
z: 0 students

A sample "p" response (from student 3737):
A sample "p" response (from student 4242):

Physics final exam question: temperature changes during heat exchange

2011-12-21T00:05:00.000-08:00

Physics 205A Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Practice Problem 14.5, Comprehensive Problem 14.75

A 0.50 kg aluminum sample at a temperature of 25° C, and a 0.50 kg iron sample at a temperature of 50° C are brought together in contact to reach thermal equilibrium. After reaching thermal equilibrium, which sample had the greatest change in temperature? Explain your answer using the properties of heat, temperature, and thermal equilibrium. Specific heat of aluminum is 900 J/(kg·K). Specific heat of iron is 440 J/(kg·K).

Solution and grading rubric:

p = 10/10:
Correct. The heat transferred from the iron sample is equal to the heat transferred to the aluminum sample as they attain thermal equilibrium. Because they have the same mass, then the iron sample, which has the smaller specific heat, will have the greater temperature change. May have explicitly solved for the final temperature of the aluminum-iron system.
r = 8/10:
As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes. Recognizes that iron has a smaller specific heat in arguing that it must have the greater temperature change, but does not explicitly note that the heat or change in internal energy is the same for both samples as they attain thermal equilibrium.
t = 6/10:
Nearly correct, but argument has conceptual errors, or is incomplete. At least discussion involves heat, specific heats, and temperature changes.
v = 4/10:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
x = 2/10:
Implementation of ideas, but credit given for effort rather than merit.
y = 1/10: Irrelevant discussion/effectively blank.
y = 1/10:
Irrelevant discussion/effectively blank.
z = 0/10:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: finalB0xs
p: 20 students
r: 9 students
t: 16 students
v: 1 student
x: 1 student
y: 1 student
z: 0 students

A sample "p" response (from student 0864):
Another sample "p" response (from student 1123):

Physics final exam problem: accelerating stacked boxes

2011-12-20T00:05:00.000-08:00

Physics 205A Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 4.142, 4.144

[20 points.] Two boxes are stacked upon each other.  A rope with a tension force of 18 N is applied as shown to the bottom box. The magnitude of the static friction force between the surfaces of the top and bottom boxes is 4.5 N. Both boxes accelerate to the right with a constant magnitude of 1.5 m/s², as they move together across a frictionless floor. Determine (a) the mass of the top box, and the (b) mass of the bottom box. Show your work and explain your reasoning.

Solution and grading rubric:

p = 20/20:
Correct. Only horizontal motion is of interest here, such that a complete free-body diagram involving vertical forces is not necessary. Newton's second law is applied to the top box, where the net force only consists of the friction force, and set equal to the mass of the top box times the given acceleration (which must be the same as the bottom box); m_top = 3.0 kg. Then Newton's second law is applied to the bottom box, where the net force is equal to the vector sum of the given applied force (right) and friction force (left, equal to the friction force of the bottom fox on the top box, due to Newton's third law), and set equal to the mass of the bottom box times the given acceleration; m_bottom = 9.0 kg. There may be minor round-off discrepancies, and skipped steps as long as the relevant application of Newton's laws and force vector directions and summations are clearly indicated.
r = 16/20:
Nearly correct, but includes minor math errors. Successful at correctly finding mass of one box only, or of both boxes combined only.
t = 12/20:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least some attempt at applying Newton's second law to part of or the whole system, but free-body diagram is problematic or fragmented; or attempt at free-body diagram with problematic application of Newton's second law, and Newton's third law.
v = 8/20:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Serious attempt at a free-body diagram, or some attempt at applying Newton's laws.
x = 4/20:
Implementation of ideas, but credit given for effort rather than merit.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: finalB0xs
p: 21 students
r: 13 students
t: 5 students
v: 7 students
x: 1 student
y: 0 students
z: 1 student

A sample "p" response (from student 3389), but applying Newton's laws correctly, but confounding N1, N2, and N3 labels:

Physics final exam problem: categorizing a cart collision

2011-12-19T00:05:00.000-08:00

Physics 205A Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 7.47, 7.49

[20 points.] A 0.40 kg cart traveling in the +x direction at 0.75 m/s collides with a 2.00 kg cart that is initially at rest. The carts are not stuck together after the collision. After the collision, the 2.00 kg cart (that was initially at rest) travels in the +x direction at 0.25 m/s. Neglect drag and friction. Find (a) the final velocity of the 0.40 kg cart, and (b) classify this collision as elastic, inelastic, or perfectly inelastic. Show your work and explain your reasoning.

Solution and grading rubric:

p = 20/20:
Correct. Finds final speed of the 0.40 kg cart, using conservation of momentum (negligible drag, friction), v_1f = -0.50 m/s. It is not known whether the carts are permanently deformed and/or energy was lost to thermal/sound systems, so collision could be either inelastic or elastic (but cannot be perfectly inelastic because the carts are not stuck together after the collision). Explicitly tests for whether or not kinetic energy is conserved using either K = (1/2)*m*v² or relative velocity exchange, and finds that since kinetic energy is conserved, this collision must be elastic.
r = 16/20:
Nearly correct, but includes minor math errors. As (p), but at least applies momentum conservation to find the correct v_1f, then tests for kinetic energy conservation.
t = 12/20:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Has correct v_1f (may have magnitude only) from momentum conservation, but does not explicitly test for energy conservation, and attempts to identify collision as elastic or inelastic on the basis of no visible deformation, which is not explicitly stated.
v = 8/20:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Application of momentum conservation, but v_1f is incorrect, with little or no test of kinetic energy conservation.
x = 4/20:
Implementation of ideas, but credit given for effort rather than merit. Discussion based on stated characteristics of collision, with no application or test of appropriate conservation laws.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: finalB0xs
p: 12 students
r: 13 students
t: 14 students
v: 8 students
x: 0 students
y: 0 students
z: 1 student

A sample "p" response (from student 3737), comparing the amounts of initial and final total kinetic energies:
Another sample "p" response (from student 2372), testing for the exchange of relative velocities:
A sample "t" response (from student 0361):
Another sample "t" response (from student 1776):
Yet another sample "t" response (from student 1995):

Physics final exam problem: disk rolling uphill

2011-12-18T06:49:00.001-08:00

Physics 205A Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 8.59, Review & Synthesis 10 (p. 311).

[20 points.] A 0.45 kg solid disk of radius 0.050 m has an initial translational speed of 2.8 m/s as it rolls without slipping across a floor. The disk begins to roll up a ramp with a horizontal level 0.80 m above the floor. Will the disk make it to the horizontal level at the top of the ramp? Neglect drag. Show your work and explain your reasoning.

Solution and grading rubric:

p = 20/20:
Correct. Sets up an energy conservation equation with changes in gravitational potential energy, translational kinetic energy, and rotational kinetic energy summing to zero (applying v = R*ω for rolling without slipping, and I = (1/2)*m*R² for a solid cylinder), and solves for y_i = 0.60 m, which is interpreted to mean that it will not reach the top of the ramp. Arithmetical
errors (± signs, cancellation, decimal point) okay.
r = 16/20:
Nearly correct, but includes minor math errors.
t = 12/20:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors.
v = 8/20:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Neglects rotational kinetic energy, thus solving for the translational speed of a sliding (point) mass. Or neglects translational kinetic energy, thus solving for the rotational speed of a cylinder given the gravitational potential energy of an equivalent point mass.
x = 4/20:
Implementation of ideas, but credit given for effort rather than merit. Garbled attempt at calculating energy terms, or may involve kinematics.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: finalB0xs
p: 23 students
r: 0 students
t: 11 students
v: 7 students
x: 3 students
y: 0 students
z: 4 students

A sample "p" response (from student 3234):
Another sample "p" response (from student 4224):

Physics final exam problem: changing string tension and standing wave mode

2011-12-17T00:05:00.000-08:00

Physics 205A Final Exam, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 11.49, Review & Synthesis 14 (p. 454).

[20 points.] A string with a length of 0.80 m between supports is stretched by a 2.3 kg mass hanging from one end. A device oscillates the n = 3 mode at 84 Hz.      Find the mass that should hang off of this string such that the same 84 Hz frequency vibrates the n = 2 mode. Show your work and explain your reasoning.

Solution and grading rubric:

p = 20/20:
Correct. Mass of the string is not provided. However:

f₃ = 84 Hz = ((3/(2*L))*sqrt(m*g/µ),

where m = 2.3 kg, µ is the linear mass density of the string; and:

f₂' = 84 Hz = ((2/(2*L))*sqrt(m'*g/µ),

where m' is the new mass that hangs off of the string when vibrating in the n = 2 mode. Equating:

f₂' = f₃,

and cancelling common factors results in:

m' = m*(3/2)^2 = 5.2 kg.

And/or may have solved for quantities such as wave speed along each string, linear mass density, etc., in intermediate steps.
r = 16/20:
Nearly correct, but includes minor math errors.
t = 12/20:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Typically calculates linear mass density µ as (2.3 kg)/(0.80 m) = 5.6 kg/m, and/or confounds µ with mass m, tension force F with frequency f, etc., but still has systematic attempt at finding linear mass density from original n = 3 case, and then feeds (erroneous) µ and/or other factors into the n = 2 case, along with other algebraic or nomenclature errors.
v = 8/20:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Some attempt at manipulating standing wave frequency equations.
x = 4/20:
Implementation of ideas, but credit given for effort rather than merit.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: finalB0xs
p: 9 students
r: 5 students
t: 23 students
v: 6 students
x: 1 student
y: 2 students
z: 2 students

A sample "p" response (from student 1124):
A sample "t" response (from student 3389):
Kudos (from student 0415):

Physics quiz question: thermal expansion of different cross-section bars

2011-12-15T00:05:00.004-08:00

Physics 205A Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 13.9

A 1.0 cm² cross-sectional area steel bar is heated up such that its length extends by by 0.1 mm. To extend a 2.0 cm² cross-sectional area steel bar by 0.1 mm, it must experience a temperature change __________ the temperature change of the 1.0 cm² cross-sectional area steel bar. (The bars have the same length.)
(A) smaller than.
(B) the same as.
(C) larger than.
(D) (Not enough information is given.)

Correct answer: (B)

The thermal expansion of a bar of length L is given by:

∆L = L*β*T,

and does not depend on the cross-sectional area of the bar.

Sections 70854, 70855
Exam code: quiz07h3A7
(A) : 15 students
(B) : 20 students
(C) : 17 students
(D) : 0 students

Success level: 38%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.71

Physics quiz question: cooling metal container with liquid contents

2011-12-15T00:05:00.003-08:00

Physics 205A Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 13.14

A metal container is filled to the brim with a liquid. If the temperature decreases, under which conditions would the liquid overflow? (There are no changes in phase.)
(A) 3α_metal > β_liquid.
(B) 3α_metal = β_liquid.
(C) 3α_metal < β_liquid.
(D) (Two of the above choices.)
(E) (All of the above choices.)
(F) (None of the above choices.)

Correct answer: (A)

If the temperature decreased, the liquid would overflow the container if the metal container contracted more than the liquid contents. This means that the volume expansion coefficient of the metal would need to be greater than the volume expansion coefficient of the liquid.

Sections 70854, 70855
Exam code: quiz07h3A7
(A) : 29 students
(B) : 1 student
(C) : 17 students
(D) : 5 students
(E) : 0 students
(F) : 0 students

Success level: 56%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.76

Physics quiz question: heat flow through window and shade

2011-12-15T00:05:00.002-08:00

Physics 205A Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 14.56

A Harvey Building Products[1] vinyl casement window has a thermal resistance of 0.33 K/watt. The temperature difference between inside and outside is 30° C. The SymphonyShades™ Virtuoso® window shade[2] is also claimed to have a thermal resistance of approximately 0.33 K/watt. If this window shade completely covers the window, the rate of heat conduction will be __________ of the original (uncovered) value.
(A) one-third.
(B) one-half.
(C) two-thirds.
(D) twice.
(E) (No change in rate of heat conduction.)

[1] R-factor = 0.33, ENERGY STAR rated, 19 square feet, http://www.harveybp.com/upload/products/literature/Harvey_AccessoryWindows_Brochure.pdf
[2] R-factor = 0.34, single-cellular light-filtering fabric, 19 square feet, http://symphonyshades.com/single_cell_shades.html.

Correct answer: (B)

The rate at which heat is conducted to the environment is given by:

(heat flow)/time = ∆T/R,

where R is the thermal resistance of the sample, and is additive for materials that are stacked in series. Thus increasing the overall thermal resistance by a factor of two will change the heat flow per time by a factor of one-half.

Sections 70854, 70855
Exam code: quiz07h3A7
(A) : 9 students
(B) : 27 students
(C) : 8 students
(D) : 7 students
(E) : 1 student

Success level: 52%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

Physics quiz question: net heat rate radiated by stove

2011-12-15T00:05:00.001-08:00

Physics 205A Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 14.65

A black wood stove has a surface area of 1.6 m² and a surface temperature of 180° C. The room temperature is 15° C. What is the net rate at which heat is radiated into the room?
(A) 67 watts.
(B) 95 watts.
(C) 3.2x10³ watts.
(D) 3.8x10³ watts.

Correct answer: (C)

The rate at which the wood stove radiates heat to the environment is given by:

(heat flow)/time = e*σ*A*(T_obj)⁴ = 3,820 watts,

which is response (D), where the temperature of the object is given in kelvins: 180° C + 273 = 453 K.

The rate at which the wood stove absorbs heat from the environment is given by:

(heat flow)/time = e*σ*A*(T_env)⁴ = 624 watts,

where the temperature of the environment is given in kelvins: 15° C + 273 = 288 K.

Thus the net rate at which heat is radiated into the environment is then:

(heat flow)/time = e*σ*A*[(T_obj)⁴ - (T_env)⁴] = 3,196 watts,

or to two significant figures, 3.2x10³ watts.

Response (A) uses the temperature difference raised to the fourth power (T_obj - T_env)⁴; response (B) is the power radiated by the stove, but using 180° C instead of 453 K.

Sections 70854, 70855
Exam code: quiz07h3A7
(A) : 3 students
(B) : 24 students
(C) : 23 students
(D) : 2 students

Success level: 44%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.46

Physics quiz question: lava lamp convection

2011-12-15T00:05:00.000-08:00

Physics 205A Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 14.8

Wax droplets in a lava lamp will rise after being heated in the base because their __________ increases, making their __________ decrease.
(A) density; mass.
(B) density; volume.
(C) mass; volume.
(D) mass; density.
(E) volume; mass.
(F) volume; density.

Correct answer: (F)

The light bulb at the base of the lava lamp heats wax suspended in fluid, which causes the wax to expand and increase in volume, decreasing in density. The expanded wax then rises, as it is now less dense than the fluid it is suspended in. Later after cooling at the top of the lamp, the wax will contract, decrease in volume, increasing in density, and subsequently sink.

Sections 70854, 70855
Exam code: quiz07h3A7
(A) : 1 student
(B) : 1 student
(C) : 0 students
(D) : 0 students
(E) : 0 students
(F) : 50 students

Success level: 96%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.12

Physics quiz archive: temperature, thermal equilibrium, heat transfer

2011-12-14T00:05:00.000-08:00

Physics 205A Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Sections 70854, 70855, version 1
Exam code: quiz07n0N3
Sections 70854, 70855 results
Quiz 7 results (max score = 30):

0- 6 :	* [low = 6]
7-12 :	********
13-18 :	*******************
19-24 :	*************** [mean = 19.2 +/- 5.7]
25-30 :	********* [high = 30]

Astronomy multiple-choice question: solar system debris and IAU classification scheme

2011-12-13T00:05:00.000-08:00

Astronomy 210 Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Refer below to the minimal qualifications established by the International Astronomical Union for a planet:

I. Orbits the sun.
II. Shape "rounded-out" by gravity.
III. Cleared/dominates orbit around sun.

Which of the following is classified as solar system debris?
(A) Pluto, a spherical body sharing Neptune's orbit.
(B) Ceres, a spherical body with an orbit between Mars and Jupiter.
(C) Cruithne, an irregularly shaped body sharing Earth's orbit.
(D) Phobos, an irregularly shaped body orbiting Mars.
(E) (More than one of the above choices.)
(F) (All of the above choices.)
(G) (None of the above choices.)

Correct answer: (C).

Solar system debris are objects that orbit the sun (meets qualification I), but are irregular in shape (does not meet qualification II), and also are unable to dominate/clear its orbit around the sun (does not meet qualification III). Thus according to the IAU classification scheme, Cruithne is the only solar system debris object in this list, as Pluto and Ceres are dwarf planets, and Phobos is a satellite.

Section 70158
Exam code: quiz07s3tI
(A) : 1 student
(B) : 2 students
(C) : 7 students
(D) : 4 students
(E) : 15 students
(F) : 1 student
(G) : 1 student

Success level: 30% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.60

Section 70160
Exam code: quiz07n0N3
(A) : 1 student
(B) : 2 students
(C) : 9 students
(D) : 2 students
(E) : 9 students
(F) : 4 students
(G) : 1 student

Success level: 40% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.75

Astronomy multiple-choice question: Amalthea and IAU classification scheme

2011-12-12T00:05:00.000-08:00

Astronomy 210 Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Refer below to the minimal qualifications established by the International Astronomical Union for a planet:

I. Orbits the sun.
II. Shape "rounded-out" by gravity.
III. Cleared/dominates orbit around sun.

Amalthea, an asteroid, was captured by Jupiter and became its satellite. Which qualification(s) changed when this happened?
(A) I only.
(B) II only.
(C) III only.
(D) Both I and II.
(E) Both II and III.
(F) Both I and III.
(G) I, II, and III.
(H) (None of the above choices.)

Correct answer: (A).

Amalthea, while an asteroid, orbited the sun (met qualification I), but did not clear/dominate its orbit around the sun in the asteroid belt (did not meet qualification III). When captured by Jupiter to become its satellite, qualification I changed, as now it no longer orbits the sun. Even though the shape of Amalthea was not discussed, it would not have changed when captured by Jupiter.

Section 70158
Exam code: quiz07s3tI
(A) : 9 students
(B) : 2 students
(C) : 6 students
(D) : 4 students
(E) : 2 students
(F) : 2 students
(G) : 2 students
(H) : 4 students

Success level: 35% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.48

Section 70160
Exam code: quiz07n0N3
(A) : 15 students
(B) : 4 students
(C) : 3 students
(D) : 2 students
(E) : 0 students
(F) : 3 students
(G) : 0 students
(H) : 1 student

Success level: 57% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38

Astronomy quiz archive: solar system

2011-12-11T00:05:00.001-08:00

Astronomy 210 Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Section 70160, version 1
Exam code: quiz07n0N3
Section 70160
Quiz 7 results (max score = 40):

0- 8.0 :
8.5-16.0 :	***** [low = 11.5]
16.5-24.0 :	**********
24.5-32.0 :	******** [mean = 24.5 +/- 8.1]
32.5-40.0 :	***** [high = 40.0]

Astronomy quiz archive: solar system

2011-12-11T00:05:00.000-08:00

Astronomy 210 Quiz 7, fall semester 2011
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz07s3tI
Section 70158
Quiz 7 results (max score = 40):

0- 8.0 :	** [low = 4.0]
8.5-16.0 :	*******
16.5-24.0 :	***************** [mean = 18.8 +/- 7.2]
24.5-32.0 :	****
32.5-40.0 :	* [high = 40.0]

Total lunar eclipse, December 10, 2011

2011-12-10T05:28:00.000-08:00

111210-1280484-1
http://www.flickr.com/photos/waiferx/6486545953/
Originally uploaded by Waifer X

Wifey X and Briquetta (puppy) watching the total lunar eclipse, December 10, 2011.

FCI post-test comparison: Cuesta College versus UC-Davis

2011-12-07T14:41:00.000-08:00

Students at both Cuesta College (San Luis Obispo, CA) and the University of California at Davis were administered the 30-question Force Concept Inventory (Doug Hestenes, et al.) during the first week of instruction.

	Cuesta College Physics 205A Fall semester 2011	UC-Davis Physics 7B Summer session II 2002
N	46 students*	76 students*
low	6	3
mean	15.2 ± 6.7	12.9 ± 5.5
high	30	26

*Excludes students with negative informed consent forms (*.pdf)

Student's t-test of the null hypothesis results in p = 0.041 (t = 2.06, sdev = 5.96, degrees of freedom = 120), thus there is a significant difference between Cuesta College and UC-Davis FCI pre-test scores.

The pre- to post-test gain for this semester at Cuesta College is:

Physics 205A fall semester 2011 sections 70854, 7085
<initial%>	= 31% ±17% (N = 57)
<final%>	= 51% ± 23% (N = 46)
<g>	= 0.28 ± 0.29 (matched-pairs); 0.28 (class-wise)

This Hake gain is in line with the previous semesters' results for algebra-based introductory physics at Cuesta College (0.25-0.33), and greater than previous gains for algebra-based introductory physics at UC-Davis (0.16), and for calculus-based introductory physics at Cuesta College (0.14-0.16), as discussed in previous postings on this blog.

Notable about this Physics 205A class at Cuesta College during this fall 2011 semester is the use of flashcards rather than electronic response system "clickers" (Classroom Performance System, einstruction.com), to engage in "think-pair-share" (peer-instruction).

D. Hestenes, M. Wells, and G. Swackhamer, Arizona State University, "Force Concept Inventory," Phys. Teach. 30, 141-158 (1992).
Development of the FCI, a 30-question survey of basic Newtonian mechanics concepts.

Previous FCI results:

Cuesta College versus UC-Davis, fall semester 2011 pre-tests.
Cuesta College versus UC-Davis, fall semester 2009 pre-tests and post-tests.
Cuesta College versus UC-Davis, spring semester 2009 pre-tests and post-tests.
Cuesta College versus UC-Davis, fall semester 2008 pre-tests and post-tests.
Cuesta College versus UC-Davis, spring semester 2008 pre-tests and post-tests.
Cuesta College versus UC-Davis, fall semester 2007 pre-tests and post-tests.

Overheard: all that glitters

2011-12-05T00:05:00.000-08:00

Astronomy 210L, fall semester 2011
Cuesta College, San Luis Obispo, CA

(Overheard while students set up their research posters for the last astronomy lab meeting.)

Student: "Do you like how I did the galaxies [at the top of the poster]?"

Instructor: "Are those [elliptical galaxy and spiral galaxy] just glitter and glue?"

Student: "Yeah. I had some space to fill in so I went with that."

Instructor: "Seriously, when was the last time you got to use glitter and glue?"

Student: (Beat.) "I'll have to get back to you on that."

Overheard: fabulous graph

2011-12-04T21:23:00.000-08:00

Astronomy 210L, fall semester 2011
Cuesta College, San Luis Obispo, CA

(Overheard while students set up their research posters for the last astronomy lab meeting.)

Instructor: "Are these data points on your graph...sequins?"

Student: "No, they're just drawn in with purple ink."

Instructor: "That's too bad." (Beat.) "Because if they were sequins, your graph would be...fabulous!"

Astronomy current events question: early pristine gas

2011-12-02T12:44:00.001-08:00

Astronomy 210L, fall semester 2011
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

John Matson, "Fresh Start: Scientists Glimpse Unsullied Traces of the Infant Universe," November 10, 2011
http://www.scientificamerican.com/article.cfm?id=big-bang-nucleosynthesis-gas

Pockets of pristine gas from the early universe were detected to have no heavy elements by observing __________ the gas clouds.
(A) no dark matter within.
(B) no massive black holes in.
(C) the gravitational redshift of.
(D) first-generation stars being born in.
(E) how quasar light passes through.

Correct answer: (E)

Student responses
Sections 70178, 70186, 70200
(A) : 5 students
(B) : 1 student
(C) : 9 students
(D) : 11 students
(E) : 20 students

Astronomy current events question: Pluto's hidden ocean?

2011-12-02T12:42:00.000-08:00

Nola Taylor Redd, "Pluto's Hidden Ocean," November 17, 2011
http://www.astrobio.net/exclusive/4343/plutos-hidden-ocean-

When NASA's New Horizons spacecraft passes by Pluto in 2015, it is expected to verify whether or not there is a subsurface ocean by looking at Pluto's:
(A) surface contours.
(B) geyser outflow composition.
(C) habitable zone.
(D) crater density.
(E) atmosphere composition.

Correct answer: (A)

Student responses
Sections 70178, 70186, 70200
(A) : 14 students
(B) : 3 students
(C) : 2 students
(D) : 2 students
(E) : 3 students

Astronomy current events question: Europa's 'Great Lake?'

2011-12-02T12:39:00.000-08:00

UTC-Austin news release, "Scientists Find Evidence for 'Great Lake' on Europa and Potential New Habitat for Life," November 16, 2011
http://www.jsg.utexas.edu/news/2011/11/scientists-find-evidence-for-great-lake-on-europa/

Based on __________, University of Texas at Austin scientists have proposed a model predicting lakes within the icy shell of Jupiter's moon, Europa.
(A) deep-penetration radar surveys.
(B) reflected light patterns.
(C) photosynthesis chemical byproducts.
(D) drilling down into the ice sheet in Antarctica.
(E) comparing images with similar features on Earth.

Correct answer: (E)

Student responses
Sections 70178, 70186, 70200
(A) : 8 students
(B) : 5 students
(C) : 2 students
(D) : 1 student
(E) : 6 students

Astronomy current events question: matter-antimatter decay imbalance

2011-12-02T12:34:00.000-08:00

Jason Palmer, "LHC Reveals Hints of 'New Physics' in Particle Decays," November 15, 2011
http://www.bbc.co.uk/news/science-environment-15734668

Preliminary observations of __________ at the Large Hadron Collider may explain why the universe is predominately matter.
(A) different particle and antiparticle decay rates.
(B) neutrinos traveling faster than the speed of light.
(C) dark matter and dark energy production.
(D) miniature short-lived black holes.
(E) lack of time-reversed big banglets.

Correct answer: (A)

Student responses
Sections 70178, 70186, 70200
(A) : 30 students
(B) : 4 students
(C) : 10 students
(D) : 2 students
(E) : 0 students

Physics midterm question: work done on diagonally-pulled crate

2011-12-02T00:05:00.004-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 6.1

A rope that makes an angle of 35° above the horizontal drags a crate across a frictionless floor. Which forces on the crate do positive work?
(A) Weight.
(B) Rope.
(C) Normal.
(D) (More than one of the above choices.)
(E) (None of the above choices.)

Correct answer: (B)

The definition of work done is:

W = F*∆r*cosθ,

and since the angle between the displacement ∆r (along the +x direction) is 90° for both the normal force and the weight force, these forces do zero work on the crate. Since the angle between the tension force of the rope and the displacement ∆r is between 0° and 90°, then the rope does positive work on the crate.

Sections 70854, 70855
Exam code: midterm02fR3q
(A) : 1 student
(B) : 30 students
(C) : 0 students
(D) : 19 students
(E) : 3 students

Success level: 57%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

Physics midterm question: horizontal, widening pipe

2011-12-02T00:05:00.003-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 9.41

The pressure of water __________ as it flows from point [1] to point [2]. (Assume ideal fluid flow.)
(A) decreases.
(B) remains constant.
(C) increases.
(D) (Not enough information is given.)

Correct answer: (D)

From applying the continuity equation:

A₁*v₁ = A₂*v₂,

the water speed at point [2] is slower than at point [1], because the cross-sectional area at point [2] is larger than at point [1].

Then from Bernoulli's equation:

0 = ∆P + (1/2)*ρ*∆(v²) + ρ*g*∆y,

the second term on the right-hand side decreases due to the decrease in speed from point [1] to point [2], while the third term on the right-hand side remains constant (no change in elevation along the horizontal pipe), thus the pressure must increase as water flows from point [1] to point [2].

Sections 70854, 70855
Exam code: midterm02fR3q
(A) : 24 students
(B) : 14 students
(C) : 15 students
(D) : 0 students

Success level: 28%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.43

Physics midterm question: piccolo versus flute

2011-12-02T00:05:00.002-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Questions 12.12, Problem 12.19

Piccolos and flutes can both be modeled as open-open pipes. If a piccolo is one-half the length of a flute, the fundamental frequency of the piccolo is __________ the fundamental frequency of a flute.
(A) one-quarter.
(B) one-half.
(C) the same as.
(D) twice.
(E) four times.

Correct answer: (D)

The fundamental frequency of a standing sound wave in an open-open pipe is given by:

f₁ = v/(2*L).

Since the piccolo is half the length of the flute, then it will have a fundamental frequency twice that of the flute.

Sections 70854, 70855
Exam code: midterm02fR3q
(A) : 2 students
(B) : 7 students
(C) : 1 student
(D) : 41 students
(E) : 2 students

Success level: 77%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.27

Physics midterm question: standing wave in warm closed-open pipe

2011-12-02T00:05:00.001-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Questions 12.1, 12.2, Problem 12.21

If the temperature of the air inside a closed-open pipe were to heat up, the speed of sound in the pipe would __________, while its fundamental frequency would __________.
(A) remain constant; remain constant.
(B) remain constant; change.
(C) change; remain constant.
(D) change; change.

Correct answer: (D)

The fundamental frequency of a standing sound wave in a closed-open pipe is given by:

f₁ = v/(4*L),

and the speed of sound waves is given by:

v = (331 m/s)*sqrt(T//(273 K)),

such that a temperature increase would increase the speed of sound, resulting in a higher fundamental frequency.

Sections 70854, 70855
Exam code: midterm02fR3q
(A) : 7 students
(B) : 7 students
(C) : 9 students
(D) : 30 students

Success level: 55%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

Physics midterm question: frequency of standing wave on a string

2011-12-02T00:05:00.000-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 11.4, Multiple-Choice Question 11.5

A cello's C-string[1],[2] has a length of 0.70 m and is stretched to a tension of 140 N. It vibrates at a fundamental frequency of 65.4 Hz. In order to decrease the fundamental frequency of this cello string, which of the following should be done?
(A) Press a finger on the string, such that a shorter length of it vibrates.
(B) Increase the tension of the string.
(C) (Both of the above choices.)
(D) (Neither of above choices.)

[1] http://www.cello.org/Newsletter/Articles/tipbook/tipbook.htm
[2] http://www.rdebey.com/string_tension.htm .

Correct answer: (D)

The fundamental frequency of a standing wave on a string is given by:

f₁ = sqrt(F/µ)/(2*L),

such that neither decreasing the length L of the string, nor increasing the tension F of the string would both result in an decrease in f₁.

Sections 70854, 70855
Exam code: midterm02fR3q
(A) : 7 students
(B) : 7 students
(C) : 9 students
(D) : 30 students

Success level: 55%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

Physics midterm question: cable-supported beam

2011-12-01T00:05:00.001-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 8.19, 8.35

[10 points.] A uniform beam is mounted on a pivot at one end, and supported at its center by a cable perpendicular to the beam. Discuss why the magnitude of the tension in the cable is less than the weight of the beam. Explain your reasoning using the properties of forces, lever arms, and torques.

Solution and grading rubric:

p = 10/10:
Correct. The ccw torque from cable equals the cw torque from weight, but the cable has a larger lever arm (L/2) than weight (L*cos(25°)/2), such that the cable tension force must be smaller than the weight force.
r = 8/10:
As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes.
t = 6/10:
Nearly correct, but argument has conceptual errors, or is incomplete. Applies Newton's first law for rotations, but r_perp discussion is garbled or missing.
v = 4/10:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to discuss torques, forces, lever arms, but Newton's first law for rotations is not clearly used. May instead use Newton's first law for vertical forces and involve the force of the pivot point, but does not clearly break up tension into vertical and horizontal components.
x = 2/10:
Implementation of ideas, but credit given for effort rather than merit. Does not discuss torques, forces, lever arms.
y = 1/10: Irrelevant discussion/effectively blank.
y = 1/10:
Irrelevant discussion/effectively blank.
z = 0/10:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: midterm02fR3q
p: 16 students
r: 3 students
t: 10 students
v: 24 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 4816):

Physics midterm question: crushing-fender car

2011-12-01T00:05:00.000-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 7.13

[10 points.] A car is retrofitted with special fenders that would completely crush on impact, such that it would be stationary (and not rebound) after crashing into the wall. Discuss why this retrofitted car would experience a smaller magnitude crash impulse than a car that would rebound slightly after crashing into a wall. Explain your reasoning using the properties of impulse and momentum.

Solution and grading rubric:

p = 10/10:
Correct. Since impulse is the change in momentum, discuss how the retrofitted car undergoes a smaller momentum change than a car that rebounds off of the wall.
r = 8/10:
As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes. May have slightly garbled definition of impulse-momentum theorem, but argument is conceptually sound.
t = 6/10:
Nearly correct, but argument has conceptual errors, or is incomplete. At least understands that ∆v term is larger for rebounding car in analyzing the car crashes with regards to momentum change.
v = 4/10:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Some attempt at applying impulse and momentum concepts, but may have involved force and/or elapsed time in argument.
x = 2/10:
Implementation of ideas, but credit given for effort rather than merit. Discussion based on how momentum or kinetic energy is
"absorbed" or "transmitted back" by crushing or rebounding fenders.
y = 1/10: Irrelevant discussion/effectively blank.
y = 1/10:
Irrelevant discussion/effectively blank.
z = 0/10:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: midterm02fR3q
p: 20 students
r: 8 students
t: 7 students
v: 11 students
x: 7 students
y: 0 students
z: 0 students

A sample "p" response (from student 0524):

Physics midterm problem: hydrostatic weighing

2011-11-30T00:05:00.001-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 9.37, 9.38

[20 points.] The average density of a person can be found by first weighing that person in air and then finding the scale reading for the person completely immersed in water (while suspended from the scale). If a person has a weight 550 N in air and has an average density of 1.05×10³ kg/m³, what would be the scale reading for the person completely immersed in water? The density of water is ρwater = 1.00×10³ kg/m³. Show your work and explain your reasoning.

Solution and grading rubric:

p = 20/20:
Correct. Finds volume of person, given density and mass (from weight in air), and calculates bouyant force on person while submerged in water. The scale reading is then the difference between the weight and the bouyant force. Proper use of Newton's first law, definition of bouyant force, and relation between mass and weight.
r = 16/20:
Nearly correct, but includes minor math errors. May have conflated mass and weight, or density values, but still clearly shows methodicaly process.
t = 12/20:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors.
v = 8/20:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. At some attempt at using Newton's laws, definition of bouyant force, and relation between mass and weight.
x = 4/20:
Implementation of ideas, but credit given for effort rather than merit. Discussion not based on methodical application Newton's laws, definition of bouyant force, and relation between mass and weight.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Sections 70854, 70855
Exam code: midterm02fR3q
p: 24 students
r: 4 students
t: 5 students
v: 8 students
x: 7 students
y: 0 students
z: 0 students

A sample "p" response (from student 3737), rounding to two significant figures during each step:
Another sample "p" response (from student 3737), rounding to two significant figures only for the very last calculation:

Physics midterm problem: bullet embedding into block

2011-11-30T00:05:00.000-08:00

Physics 205A Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 7.43, 7.44

[20 points.] A 0.0036 kg Nosler® Ballistic Tip® V-Shok® .223 Remington bullet[*] is shot and collides horizontally with speed of 988 m/s into a 2.6 kg block of wood. The bullet embeds itself in the block and the block (and embedded bullet) slides along a horizontal frictionless surface. What is the final kinetic energy of the sliding block and embedded bullet system? Show your work and explain your reasoning.

[*] Source: http://www.federalpremium.com/products/compare/rifle_compare.aspx.

Solution and grading rubric:

p = 20/20:
Correct. Applies momentum conservation to the perfectly inelastic collision between bullet and block to find the final velocity of bullet/block, and then calculates the final kinetic energy of bullet/block.
r = 16/20:
Nearly correct, but includes minor math errors. Momentum conservation applied to successfully find the final velocity of bullet/block, problematic kinetic energy calculation.
t = 12/20:
Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Only momentum conservation applied to successfully find the final velocity of bullet/block. No kinetic energy calculation.
v = 8/20:
Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Garbled attempt at momentum conservation, may or may not have kinetic energy calculation.
x = 4/20:
Implementation of ideas, but credit given for effort rather than merit. Does not apply momentum conservation.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Education research: college physics midterm statistics

2011-11-29T00:05:00.000-08:00

Cuesta College Physics 205A (college physics, algebra-based, mandatory adjunct laboratory) students students take their first midterm on kinematics, Newton's laws, and circular motion in the eight week of instruction.

The midterm consists of five multiple-choice questions, two short-answer questions, and two worked-out problems, to be completed within 80 minutes (the length of a regularly-scheduled lecture).

Grading statistics:

Cuesta College
Physics 205A fall semester 2011 sections 70854, 70855 
Exam code: midterm02fR3q
Midterm 2 results (N = 53, max score = 75):
 0-15 :   
16-30 : **  [low = 22]
31-45 : ***************
46-60 : ******************  [mean = 52.2 +/- 12.3]
61-75 : ******************  [high = 72]

The order in which students turned in their completed midterms was recorded, beginning approximately 20 minutes after starting, to 80 minutes after starting. With a linear regression r² value of 0.0434, there is no significant correlation between the completion order c turning on the midterm and resulting score S (S = -0.1685c + 56.966).

Astronomy midterm question: supergiants larger than same-temperature main-sequence stars?

2011-11-28T00:05:00.000-08:00

Astronomy 210 Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

24gurl: How do astronomers conclude that a supergiant star is larger than a main-sequence star of the same temperature?
Roger: The supergiant star is more luminous than the main sequence star of the same temperature. The only way that a supergiant could be more luminous than the main sequence star is if it is larger, the luminosity is proportional to the star's area...

Discuss whether or not if this answer is correct, and how you know this. Explain using Wien's law, the Stefan-Boltzmann law and/or an H-R diagram.

*Source: http://answers.yahoo.com/question/index;_ylt=AomJCCm4mAidgSmONGtTlf8jzKIX;_ylv=3?qid=20100217203829AADBeYk.

Solution and grading rubric:

p = 20/20:
Correct. Uses Stefan-Boltzmann law and/or interprets H-R diagram to show that supergiants must be larger than main sequence stars of the same temperature in order to be more luminous than the main sequence stars.
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use Wien's law, H-R diagram and/or the Stefan-Boltzman law.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Discussion not based on Wien's law, H-R diagram and/or the Stefan-Boltzman law.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:Section 70158
Exam code: midterm02s3Ar
p: 16 students
r: 5 students
t: 3 students
v: 9 students
x: 0 students
y: 1 student
z: 0 students

A sample "p" response (from student 1210), with a bonus illustration:

Education research: introductory astronomy midterm statistics

2011-11-27T22:47:00.000-08:00

Cuesta College Astronomy 210 (introductory astronomy lecture) students take their second midterm on spectra, stars, galaxies and cosmology in the fourteenth/fifteenth week of instruction.

The midterm consists of ten multiple-choice questions (with partial credit for multiple-choice), and three short-answer questions (graded with a standardized rubric), to be completed within 80 minutes (the length of a regularly-scheduled lecture).

Grading statistics:

Cuesta College
Astronomy 210 fall semester 2011 section 70158
Midterm 2 results (N = 34, maximum possible score = 100):
   0- 20.0 :   
20.5- 40.0 : **  [low = 38.0]
40.5- 60.0 : *************
60.5- 80.0 : *********  [mean = 66.1 +/- 16.9]
80.5-100.0 : **********  [high = 96.5]

One student was excluded from the linear regression due to taking the midterms at other scheduled times (and thus was not ordered with the rest of the class). With a linear regression r² value of 0.0296, there is no significant correlation between the completion order c turning on the midterm and resulting score S (S = 0.2791c + 61.108).

Grading statistics:

Cuesta College
Astronomy 210 fall semester 2011 section 70160
Midterm 2 results (N = 28, maximum possible score = 100):
   0- 20.0 :   
20.5- 40.0 : **  [low = 39.0]
40.5- 60.0 : *****
60.5- 80.0 : ************  [mean = 70.8 +/- 16.9]
80.5-100.0 : *********  [high = 96.0]

Four students were excluded from the linear regression, two from clerical errors in recording their completion order, and two due to taking the midterms at other scheduled times (and thus were not ordered with the rest of the class). With a linear regression r² value of 0.0562, there is no significant correlation between the completion order c turning on the midterm and resulting score S (S = 0.532c + 66.663).

Online reading assignment question: helpful/unhelpful Midterm 2 astronomy study tips

2011-11-27T21:55:00.000-08:00

Astronomy 210 Reading Assignment 12, fall semester 2011
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

Describe something notable that either helped or did not help with studying for this midterm. Selected comments may be discussed in class. (Graded for completion.)

The following are all of the student responses to this question, verbatim and unedited.

"What does CMB look at again?"

"no question"

"what movie are we going to watch on extra credit day?"

"Can we do lots of flashcard questions in class on Monday?"

"No comment"

"Do you like In-N-Out?"

"if you were to take the midterm, would you get 100%?"

"What inspired you to teach astronomy?"

"Flashcard questions definitely help me understand the material better."

"No questions."

"i cant it would be helpful to get our activies back to study instead of the blank one on online"

"I don't have one this week, thank you"

"what is your favorite type of star"

"What is your favorite part of Astronomy?"

"How long have you been teaching?College? High school? Other?"

"None"

"No comment."

"Can we go over all or most of the flash card questions?"

"Was Jupiter going to become another sun and is one of Jupiter's moon like an early earth?"

"I'll give it my best like I did on the last midterm."

"Superman can fly at diffferent speeds. Explanation?"

"Do worms holes actually exist and is possible to travel using them?"

"good luck everyone!"

"none."

"Can you go easy on us please?"

"Can you devote this up coming class to pure review and the next one midterm?!"

"did you play sports in high school or college?"

"Thanksgiving is next week!"

"None"

"Monsters vs Aliens...whats real and whats a bunch of bull?"

"Can you make a detailed list for what we need to know for the final?"

"Yay for extra credit!"

"iPhone Or droid?"

"how was you week?"

"like that there is a review before the midterm"

"A please... :)"

"surprise super muffin party. please?"

"whats your favorite Thanksgiving dish?"

"What's the multiverse theory?"

"yo ho ho"

"once again, why r we still doing this?"

"Do you watch LOST?"

"cant think of a comment"

Online reading assignment question: confusing Midterm 2 astronomy topics

2011-11-27T21:39:00.000-08:00

Astronomy 210 Reading Assignment 12, fall semester 2011
Cuesta College, San Luis Obispo, CA

111127-Astr210-Midterm2-confusing
http://www.flickr.com/photos/waiferx/6416615959/
Originally uploaded by Waifer X

Wordle.net tag cloud for confusing topics covered in Midterm 2, generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/4480693/Untitled).

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

List at least three words describing confusing subjects covered in class (up through this midterm). (Graded for completion.)

[Responses have been edited to consolidate related common subjects.]

Student responses
Sections 70158, 70160

redshifts, antimatter, matter
spiralarms, supernovae, darkmatter
stars evolution, blackholes, neutron stars
halolusters, bigbang, darkmatter
greenhouseeffect, platetectonics, quantummechanics
reionization, gaps, pairproduction
Sun photosphere chromosphere corona, spectra, stars evolution
Sun, atoms
bigbang, milkyway spiralarms
space, stars, darkmatter
dontknow
fusion, nebulae, blackholes
reionization
spiralarms, antimatter, darkmatter
Jovian, parsecs, arcseconds
stars evolution, giants, mainsequence stars
lookbacktime, lighttravel
supernovae
Wienslaw, StefanBoltzmann, darkmatter
fusion, density, nucleosynthesis
bigbang, spectrum, luminosity
supernovae, planets, platetectonics
everything
planets formation atmospheres gases, stars formation, bigbang
darkmatter, blackholes, galaxies
Mercury Moon
bigbang universe, everything dontknow photons
stars evolution, darkmatter, lookbacktime
nothing
StefanBoltzmann redshift greenhouseeffect
fusion, parsecs, stars
researchquestions
parsecs, haloclusters, disk halo stars
spiralarms, galaxies, spiralarms
bigbang, stars, space
darkmatter, fusion, mainsequence stars
annihilation, recombination, reionization, nucleosynthesis, pairproduction
dontknow
lightspeed, housepartymodel, mainsequence stars
haloclusters, spiralarms, terrestrial planets
stars evolution
nothing
galaxies, spiralarms, stars, stuff
stuff, giants, stuff

Describe your most confusing subject, and briefly explain why this subject confused you. (Graded for completion.)

The following are all of the student responses to this question, verbatim and unedited.

"The timeline of how the universe is believed to have been formed is confusing with all of the details that must be remembered"

"spiral arms are most confusing because i never fully understood how some parts of a galaxy are formed."

"massive star death, had trouble remembering each one"

"Globular clusters, I am unclear as to what they are and will have to read up about them before the midterm."

"I still don't understand how electrons jump up or emit."

"The things that I mentioned above this question are the main topics that are confusing to me. I just don't get it :/"

"the sun's layers, because they all are so close together and I had never thought of the sun as three separate things before."

"There was a lot to cover about the sun and how generally functions"

"The most confusing subject would be the Big Bang because it is hard to grasp how the universe began."

"Dark matter because we know it's there but don't know what it is."

"i get the all the concepts nothing pops out at me"

"I will be honest, the whole thing is confusing"

"big bang theory and the expansion of space"

"Spiral arm are confusing because I missed that day in class."

"There isn't anything that's super confusing."

"medium mass stars"

"It was kind of hard understanding and calculating the age of star and figuring out its lookback time."

"I just missed the lecture on supernova"

"I would say Wien's law and Stefan's law. I always seem to get stuck on mixing these two laws up and forgeting what the difference is between them."

"The origins of the universe is a bit confusing with having to indicate what created what with the photons indicating the mass of the universe."

"luminosity, temp, and size"

"..."

"Dont own the book."

"big bang, insane trying to imagine it"

"blackholes, it doesn't make sense that so much mass can be condensed into the same amount of space."

"I just need to learn more about them I'll study well"

"^ I always think I'm prepared for it, but the questions you ask always seem se=o detailed and i don't have all the answers. I'm trying to hard."

"the birth life and death of stars for some reason just confuses me."

"I dont think anything will be that confusing"

"I had to make sure to memorize the equation for the Stephan-Boltzmann Law. It's not always easy to remember off-hand."

"To me a confusing subject was at what time what part of our galaxy we will be able to see"

"The essay questions"

"The disc and halo stars is the most confusing to me because of the different terms for both of them in the book."

"It's hard to explain why the galaxy is flat and wide. The milky way is also a tough subject to describe."

"how far things are..."

"fusion just gets confusing with the protons and how they work"

"remebering all the steps in each pase of each stars life and the big bang"

"my most confusing subject black radiation. i didn't get much out of the book about it."

"The light speed threw me off guard with the years and detail of the telescopes."

"How the spiral arms in galaxies form. I just don't get it"

"I couldn't touch any of it.. i'm a hands on learner"

"vague questions posed on exams."

"I'm confused about some of the galaxy swirls and arms and how to tell if the shape based on those."

"progression of stars sooo much memorization"

Online reading assignment question: interesting Midterm 2 astronomy topics

2011-11-27T21:30:00.000-08:00

Astronomy 210 Reading assignment 12, fall semester 2011
Cuesta College, San Luis Obispo, CA

111127-Astr210-Midterm2-interesting
http://www.flickr.com/photos/waiferx/6416615699/
Originally uploaded by Waifer X

Wordle.net tag cloud for interesting topics covered in Midterm 2, generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/4480562/Untitled).

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

List at least three words describing interesting subjects covered in class (up through this midterm). (Graded for completion.)

[Responses have been edited to consolidate related common subjects.]

Student responses
Sections 70158, 70160

dense, warm, monolithic
bigbang, MilkyWay, lookbacktime
bigbang, mainsequence, terrestrial planets
expansion, MilkyWay, bigbang
photons, darkmatter, and blackholes
greenhouseeffect, blackholes planets
MilkyWay, stars, luminosity, bigbang
Sun, formation stars MilkyWay
starclusters, bigbang
space, stars, gravity
galaxies, evolution Sun
awesome, confusing, loud
stars galaxies universe
lithium, supernovae, blackholes
MilkyWay, terrestrial, planets
blackholes, darkmatter, halo
galaxies, MilkyWay, collapse
lookbacktime
darkmatter, supernovae, blackholes, planetarynebulae
luminosity, nebula, spiralarms
housepartymodel, PimpStarRims, Haterade
supernovae, bigbang, MilkyWay
bigbang, universe, blackholes, antimatter
platetectonics, lightyears, stars evolution
stars, darkmatter, blackholes
stars housepartymodel
blackholes, planets darkmatter
MilkyWay, galaxies, stars
extrasolar planets, galaxies, stars evolution
nebulae galaxies stars evolution
space darkmatter
heattransfer research temperature difference
nebulae, mainsequence stars, terrestrial planets
bigbang time craziness
time, space, stars
moonphases, constellations, galaxies
stars bigbang lookbacktime
pulsars, nebulae, novae
mass, bigbang, greenhouseeffect
bigbang, darkmatter, antimatter
convection, craters, yeah
bigbang universe, blackholes, antimatter
blackholes, galaxies, stars
mainsequence, stuff, blackholes

Describe your most interesting subject, and briefly explain why this subject interested you. (Graded for completion.)

The following are all of the student responses to this question, verbatim and unedited.

"Formation theories behind galaxies. Looking at all of the colorful details really looked awesome"

"look back time is the most interesting because the stars we see now in the sky were made years ago"

"Big bang, it explains how the universe was created"

"The Milky Way because it is our galaxy."

"Black holes, because they bend space time."

"Black holes are interesting to me. They're just awesome!"

"the Big Bang, because I didn't ever really understand how everything supposedly started out, and now it all makes a lot more sense."

"The Milky Way, because I did not realize how enormous it really is."

"The most interesting subject for me would have to be the Milky Way, mainly because it is where the Earth is located and that it does affect us."

"How the universe is expanding. It's mind-boggling."

"the galaxy how we r able to see i did not know how limted we r and how big everything else is"

"the moon phase, I like to watch the moon"

"star formation"

"The beginning of the universe, specifically the creation of Lithium and the fact that more is not being made any where in the universe"

"I like learning about the Milky Way"

"Look back time into the universe because it's interesting to see how everything was before the big bang"

"I loved learning about the different aspects of galaxies, and how our galaxy was formed."

"I thought that it was cool that you could see into the past even though it has changed to the present."

"I found supernovas to be interesting because before we went over it I thought that it was something that just happens to stars when something goes wrong. I had no idea that they were one of the causes on how a new solar system is formed."

"The look-back times of stars was intriging because it indicates that not only does a star give light even when it's dead, but how expansive the universe is with how long the light travels."

"Features of other planets/ plate tectonics"

"..."

"creation of the universe, its pretty interesting to find out how it was all created and how it all works."

"big bang, the creation of who and what we are"

"dark matter, it's interesting and mysterious."

"Frequency of stars..it's nice to know what stars are out there"

"Black Holes"

"the different planets in relation to ours."

"I find all three things interesting because I've never studied them before"

"I was most interested in how spiral arms are formed in galaxies. It was fascinating to learn how they can be created when a galaxy devours smaller star clusters."

"The concept of our place in our galaxy and just how small our planet truely is in comparison"

"Big bang How the earth and it's moons got here"

"I thought the Nebula's were the most interesting because of the different kinds and the different ways they are produced."

"I loved learning about the big bang because I got to argue with my mom's jerk fiancé about it."

"The big bang, because its how we came to be"

"big bang, i always wondered what started it all and how and the details"

"Stars life and death and how they come n leave to"

"nebula, because it's an awesome sounding word."

"The Big Bang would have to be the most interesting, because it is a big part of history and its interesting to know how it happened."

"How we think the big bang happened because of the whole anti matter thing and how all of the matter in our universe is from a mistake"

"I enjoyed learning about convection and different laws because it had real world application"

"creation of the universe, its pretty interesting to find out how it was all created and how it all works."

"I enjoyed learning about the big bang; it's a subject that is universally (no pun intended) known, yet I had no idea the real event."

"supernova awesome"

Online reading assignment question: helpful/unhelpful Midterm 2 physics study tips

2011-11-27T17:11:00.000-08:00

Physics 205A Reading Assignment 24, fall semester 2011
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

Describe something notable that either helped or did not help with studying for this midterm. Selected comments may be discussed in class. (Graded for completion.)

The following are all of the student responses to this question, verbatim and unedited.

"Practice practice practice"

"studying with __________"

"Studying in chunks so it's not so overwhelming and cramming can be avoided."

"working out problems in class on thursday"

"focus helps, procrastination doesn't"

"It helps to study with other people... It also helps to do some of the homework problems and quiz problems again. It does not help when you are completely lost and can't make sense of physics."

"Flashcards and reviewing quizzes helps."

"study groups."

"Skyrim"

"Going through homework problems again and re-taking the quizzes/ flashcard questions."

"to study"

"it doesnt help when its boring it tends to make you not want to study"

"Please email the student an in detailed study guide with needed formulas and an actually list of things we need to know. the book is extremely messy"

"having multiple midterms at once doesnt help this class. i need to study physics"

"Ask for help if you don't know what the question is asking/giving. Examine the applicable formulas and check off what you know."

"Wheaties.nuff said"

"reviewing old quizzes helps me."

"Homework"

"tutor and just do problems"

"Flashcard questions only help a little. Doing more problems help a lot more. Not only from the book because the book problems can be confusing, but also maybe made up problems from you."

"Going over all of the homework for the chapters that will be on the midterm help a lot."

"Doing practice problems similar to the ones on the class calendar to get more practice on the specific subjects on the test."

"doing sample problems really helps"

"group studying"

"cute girl that doesn't know physics and just wants to hot tub does NOT help me study"

"What helped me tremendously was taking advantage of your office hours to ensure that I fully understood the concepts so that I could study effectively."

"coffee."

"Re-doing the homework and quizzes is definitely the most helpful for me."

"Drink Green Tea; no sugar no additives; helps you concentrate."

"P-Dogg's blog! Thank god for this!"

"Getting an understanding of the overall specific topic helps a great deal to understand how to use the formulas."

"studying with __________"

"Redoing the homework problems really helps me to study."

"practice problems"

"procrastinating does not help, studying does help! =P"

"Having a friend that is a physics major"

"i really like your blog when you write things out step by step it really helps"

"Don't get senioritis and focus on what you are doing"

"doing flachcard questions and reworking the homework problems based around short answer and worked out problems on the study guide"

"It's easy to get overwhelmed with the amount of information we have to sort out before we come to take the test. My advice is to not get narrow-minded and keep a brief study on all the subjects"

Online reading assignment question: confusing Midterm 2 physics topics

2011-11-27T17:04:00.000-08:00

Physics 205A Reading Assignment 24, fall semester 2011
Cuesta College, San Luis Obispo, CA

111127-Phys205A-Midterm2-confusing
http://www.flickr.com/photos/waiferx/6415132437/
Originally uploaded by Waifer X

Wordle.net tag cloud for confusing topics covered in Midterm 2, generated by responses from Physics 205A students at Cuesta College, San Luis Obispo, CA (www.wordle.net/show/wrdl/4480072/Untitled).

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

List at least three words describing confusing subjects covered in class (up through this midterm). (Graded for completion.)

[Responses have been edited to consolidate related common subjects.]

Student responses
Sections 70854, 70855

leverarms, buoyancy, torque
flow, inertia, gravity, flow
fluids, SHM, waves
strings waves density
physics physics physics
torque, buoyancy, flow, leverarms, rotations
buoyancy, fluids, pressure
leverarms
formulas, collisions, inertia
energy density conservation, SHM, rotations, energy
everything
everything
studyguides flashcardquestions
buoyancy, momentum, leverarms
collisions, formulas
buoyancy, buoyancy, buoyancy
torque leverarms
fluids, waves, buoyancy
fluids, buoyancy, energy conservation
buoyancy, torque, energy conservation
difficult, unrelenting, complex
Zerg torque conservation
buoyancy impulse pendulum
impulse momentum, collisions, density
buoyancy, torque, flow
work, energy conservation, torque
everything, everything, ahhh :(
pressure, fluid flow, pressure
friction friction friction
energy, buoyancy, momentum
collisions
impulse momentum, buoyancy
buoyancy stress strain
statics, momentum, stress strain
density, buoyancy, Zerg
forces, leverarms, torque
leverarms, torque, friction collisions
stress strain energy rotations inertia
difficult confusing hard
rotations, expansion, pressure
standingwaves, momentum, conservation, fluids, flow
pressure, buoyancy, friction
waves frequency

"Torque because it doesn't make sense to me."

"inertia, confusing"

"Fluids. It was a very broad chapter and I didn't master any part of it very well. The equations and math confuse me."

"waves, its a very odd concept for me to grasp"

"word problems"

"torque. too many weird values and parts- what the heck is a lever arm? what is an r perp? why does the T for torque look like it is sitting down?"

"Buoyancy was difficult to understand probably because I missed the lectures."

"Drawing lever arms, and knowing which lines are which."

"Trying to remember how to apply all of the different formulas is difficult for me."

"Torque because I'm still confused on determining forces and magnitude acting on the objects."

"torques"

"physics is confusion"

"Uelas and Krot"

"wave nature because i have no time the past two weeks:("

"Momentum is the most confusing subject to me on this upcoming midterm because the questions regarding momentum always are the hardest to decipher."

"I understand most of it, but it takes to long to solve a problem in a timed test setting so I need to practice more."

"Lever arms are still very confusing for me because I always seem to miss one step."

"For whatever reason I've always had more trouble with static fluids than dynamic fluids. But both subjects can be confusing at times."

"fluid, don't even know how to start it, and for other problems just sometimes don't know what is 0 and know what cancel out"

"Buoyancy and Perfectly Inelastic collisions. Instead of going over the basic concepts with flashcard questions for most of the time in class, I believe that we should do more problems in class because when we do problems we learn the basic concepts as well."

"Standing waves are most confusing because i'm having trouble comprehending resonant frequencies."

"The problems that are more complicated (like 7.43) usually mess my up. anything beyond a 'plug and chug' usually takes allot of practice for me to make sure I dont get hung up on anything. As for the zerg, they're just jerks."

"I guess i was having trouble with drawing the force diagrams accurately for these problems"

"collisions and energy conservation was the most confusing."

"buoyancy, i didnt learn it ever"

"While I feel like I understand the concept of torque, sometimes I have trouble finding r perp correctly especially when you have angles that require you to use sin, cos, tan to complete the problem."

"lever arms."

"Pressure, I just didn't get enough explanation of the equations"

"Fluid Physics - I don't know; that whole 'buoyancy' thing still irks me."

"bouyant forces, it is confusing because i haven't spent the necessary time to cover the material like i would like to."

"The problem we went over in class 7.44, WHAT THE HELLLLLLLL (P)"

"lever arms, i cant ever draw the line of motion"

"Nothing!"

"motionless, things without motion does not make sense"

"Energy conservation, mostly because we did not use it as much."

"Torques, I get really frustrated with the right hand rule."

"friction with perfectly elastic situations."

"Kinetic rotational inertia was difficult because my algebra is weak and i have trouble moving around mathematical symbols on either side of the equation such."

"Waves because there are a lot variables"

"my main problem is all circluar motion and rotational stuff because I have a hard time calculating it"

"I still can't grasp my mind around how a object/material will resonate at a certain frequency."

"bouyancy is kind of difficult to understand at first but when it is understood it is more interesting than hard"

"The most confusing part is remembering what all the variables are used for what and what their SI units are."

Online reading assignment question: interesting Midterm 2 physics topics

2011-11-27T16:57:00.000-08:00

Physics 205A Reading Assignment 24, fall semester 2011
Cuesta College, San Luis Obispo, CA

111127-Phys205A-Midterm2-interesting
http://www.flickr.com/photos/waiferx/6415132221/
Originally uploaded by Waifer X

Wordle.net tag cloud for interesting topics covered in Midterm 2, generated by responses from Physics 205A students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/4480066/Untitled).

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

List at least three words describing interesting subjects covered in class (up through this midterm). (Graded for completion.)

[Responses have been edited to consolidate related common subjects.]

Student responses
Sections 70854, 70855

collisions, momentum, impulse
momentum, collisions, pressure
torque, stress, strain, pendulum
pressure, strings, stress, strain
physics physics physics
sound, waves, collisions
momentum, torque, buoyancy
density
torque, buoyancy, conservation
buoyancy, collisions, momentum
momentum, torque, inertia
nothing
pendulum, massspring
buoyancy, momentum, leverarms
energy, torque, Eureka!
torque, momentum, collisions
collisions, buoyancy, momentum
fluids flow, sound, stress strain
equations, fluids, work
torque, energy, conservation, momentum
fascinating, informative, simple
torque momentum, conservation work
stress, strain, forces leverarms
collisions, buoyancy, torque
sound, SHM, tension
buoyancy, momentum, conservation, sound
leverarms, buoyancy, momentum
torque, waves, collisions
resonance bridges
impulse, momentum, forces, collisions
buoyancy forces, torque
centerofgravity, torque, stress, strain
buoyancy, conservation, momentum
collisions, statics, collisions
fluids, flow, density, paranormalactivity
impulse, collisions, energy
collisions, impulse, momentum, leverarms
standingwaves sound buoyancy
hard harder hardest
sound, standingwaves, torque
fluids, flow, buoyancy, SHM
buoyancy, torque, momentum
buoyancy, energy pressure

"Perfectly inelastic collision because it's fun to watch things crash and calculate things about it"

"densities, easy to do"

"Torques, because it's the topic I understood most conceptually and mathmatically."

"momentum conservation"

"sound waves, because its something we can't always see"

"Ch 12- speed of sound was most interesting because it was most applicable to my life. I have played instruments before (wind and string) so it is cool to see how air flows and frequency changes."

"Momentum, Collisions, Torque"

"Using relative buoyancy to calculate the density of an object, because it was a fun lab."

"Torque. I liked it because it is fairly simple to get the hang of and it's fun to see it's application in real life."

"Pressure and buoyancy are most interesting because they directly supplement material I teach at my job."

"momentum, because it describes how to objects interact with ea. other on impact"

"nothing"

"definitely wavelengths and frequencys"

"bouyancy cuz it has a different application that the word"

"The most interesting subject to me that will be covered in this midterm would be stress and strain, you pick one and you'll most likely get both, anyways this subjects interests me the most due to common relevancy it has to everyday life."

"Torque, I understand it well. Plus its helpful information!"

"I really like buoyant forces because the concept was easy for me to understand."

"tress/Strain. I recently took ENGR 252. That is the basis of the class and has always interested me."

"energy conservation"

"Torque."

"Torque, because i find it easy to calculate. It just makes sense."

"there just the most important topics"

"I think elastic forces would be cool to see on a larger scale"

"buoyant forces were the most interesting because they worked counterintuitively."

"harmonic motion, it is cool."

"Sound waves are my most interesting subject of this midterm. It's just really interesting to learn about how something works that is present in you life 24/7!"

"momentum because you were able to relate it to real life car crashes"

"Waves, I had never understood exactly how sound worked, and I found this a fascinating explanation of it."

"lever arms, and I'm not sure. Now when I see a bridge, I see math equations."

"collision's; since the semester started this particular subject interested me the most, no exact explanation but I enjoy this subject."

"i liked the buoyancy forces because i could apply them outside and FINALLY understand it, the lab helped a lot"

"collision/elasticity - it is easy for me"

"I like perfectly inelastic collisions"

"collisions, car crashing are interesting"

"density, because I finally discovered how hyrdrolic pistons work."

"Kinetic energy was the most interesting subject because I like they way the equations work."

"perfectly inelastic, the overall thought process of the problem is what interests me over other physic categories."

"Fundamental Frequencies because i got to learn how bridges fall apart!"

"Torque because I can apply it to working with tools"

"i enjoy real world examples like waves that we see and hear every day"

"'hydrostatic weighing' is a cool alternative method for finding weight and density"

"i like how torque is determined with the lever arms and forces and the fact that if you have a bigger lever arm less force is required to obtain the certain amount of torque"

"Conservation of energy is very interesting to me because the fact that energy is never created or destroyed."

Astronomy midterm question: blue supergiants just as bright as red supergiants?

2011-11-27T00:05:00.000-08:00

Astronomy 210 Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

P-d*g: Is it possible that a blue supergiant can be as bright as a red supergiant, (assuming they are the same distance from Earth)?
per..gogy: Technically the blue supergiant would be the brighter one. Blue stars are more luminous than red stars...

Discuss whether or not if this answer is correct, and how you know this. Explain using Wien's law, the Stefan-Boltzmann law and/or an H-R diagram.

*Source: http://answers.yahoo.com/question/index;_ylt=Ail4K8XZxUHaPes.TGialC7sy6IX;_ylv=3?qid=20110602185220AATh4tm.

Solution and grading rubric:

p = 20/20:
Correct. Wien's law: blue stars are hotter, and are located on the left side of an H-R diagram, while red stars are cooler, and are located on the right side. Uses Stefan-Boltzmann law and/or interprets H-R diagram to show that either (a) blue supergiants and red supergiants can have the same size, such that the blue supergiants (being hotter) are more luminous; or (b) blue supergiants and red supergiants can have the same luminosity, but the blue supergiants (being hotter) are smaller in size.
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use Wien's law, H-R diagram and/or the Stefan-Boltzman law.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. Discussion not based on Wien's law, H-R diagram and/or the Stefan-Boltzman law.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:Section 70160
Exam code: midterm02n1cT
p: 13 students
r: 6 students
t: 6 students
v: 3 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 8386), discussing how the blue supergiant while hotter, would be smaller than the red supergiant in order to have the same luminosity:
Another sample "p" response (from student 1027) instead arguing that a blue supergiant will be brighter than a red supergiant, assuming that they are the same size:

Astronomy midterm question: red dwarf vs. massive main-sequence star metallicity

2011-11-26T00:05:00.000-08:00

Astronomy 210 Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

P-d*g: Which star today would have more metals: a red dwarf or a massive main-sequence star?
q...phobe: I'm guessing a massive main-sequence star; [because] a red dwarf is likely very old...

Discuss whether or not if this answer is correct, and how you know this. Explain using the properties and evolution of stars.

*Source: http://answers.yahoo.com/question/index;_ylt=AizYMyQpnYRTbpkhlxBd0sjsy6IX;_ylv=3?qid=20110601124741AA76NMC.

Solution and grading rubric:

p = 20/20:
Correct. Understands that (a) older stars are metal-poor having formed from essentially just hydrogen, while newer stars are metal-poor, having formed from hydrogen enriched with metals produced by previous generation stars; and (b) red dwarfs take a long time to become main sequence stars, such that they had to have started forming a long time ago, are thus are metal rich, while massive stars take a short time to form, such that they formed recently, and thus are metal poor.
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of the two points (a)-(b) is correct, other is problematic.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Only one of the two points (a)-(b) correct, other is missing, or both are problematic.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Garbled discussion of properties and evolution of stars, such as breaking down of metals; masses and evolution rates.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Section 70158
Exam code: midterm02s3Ar
p: 9 students
r: 3 students
t: 14 students
v: 8 students
x: 0 students
y: 0 students
z: 0 students

Section 70160
Exam code: midterm02n1cT
p: 9 students
r: 3 students
t: 9 students
v: 6 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 2541):
Another sample "p" response (from student 1863), using a "House Party" analogy:
Yet another sample "p" response (from student 1985), lavishly illustrated:
A sample "v" response (from student 0628), where older stars would have had more time to absorb metals than recent stars:
Another sample "v" response (from student 1226), where older stars have more time to break down metals:
Yet another sample "v" response (from student 1559), where older stars have more time to fuse metals by breaking them down:

Astronomy midterm question: you at where big bang started?

2011-11-25T00:05:00.000-08:00

Astronomy 210 Midterm 2, fall semester 2011
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

sai: We know that [the] big bang created everything we know today, but if it formed the universe where did the big bang take place?!
Dude: Right where [you] are standing.

Discuss why this answer is correct, and how you know this. Explain using observations and evidence related to the Hubble law.

*Source: http://answers.yahoo.com/question/index;_ylt=AqdNK2oFrbbdDJHHcjwfjP4jzKIX;_ylv=3?qid=20100926113402AAQcp5I.

Solution and grading rubric:

p = 20/20:
Correct. Understands that (a) Hubble's law is that the recession velocity of galaxies is proportional to distance (greater redshift of absorption lines for distant galaxies compared to nearby galaxies), corresponding to the expansion of space between galaxies, and (b) extrapolating time backwards means that the distance between everything was zero, thus any location can be said to be where the bang bang took place (or may instead argue for no unique center of expansion for expanding-space-between-galaxies universe).
r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of the two points (a)-(b) is correct, other is problematic.
t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Only one of the two points (a)-(b) correct, other is missing, or both are problematic.
v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Discussion based on evidence of the earlier stages in the history of the universe, with little or no substantive discussion of Hubble's law, such as everything was created by the big bang, therefore everything can be said to be where the big bang took place.
x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit.
y = 2/20:
Irrelevant discussion/effectively blank.
z = 0/20:
Blank.

Grading distribution:
Section 70158
Exam code: midterm02s3Ar
p: 4 students
r: 11 students
t: 9 students
v: 7 students
x: 3 students
y: 0 students
z: 0 students

Section 70160
Exam code: midterm02n1cT
p: 7 students
r: 7 students
t: 7 students
v: 4 students
x: 2 students
y: 1 student
z: 0 students

A sample "p" response (from student 1027):
A sample "v" response (from student 1177):
Another sample "v" response (from student 8436), still showing the astronomy love:

Physics quiz question: stress, strain on bricks

2011-11-24T00:05:00.000-08:00

Physics 205A Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 10.4

A load is to be supported by a brick placed in either of two orientations. Which orientation of the brick will require a greater force to compress by 0.1 mm?
(A) Orientation (A).
(B) Orientation (B).
(C) (There is a tie.)
(D) (Not enough information is given.)

Correct answer: (A)

Hooke's law is given by:

(F/A) = Y*(∆L/L),

or:

F = Y*∆L*(A/L),

where Y and ∆L is the same for both bricks. The brick with orientation (A) has a larger cross-sectional area A that force is applied to, and also a shorter L along the direction that force is applied, such that it will require more force than the brick with orientation (B).

Sections 70854, 70855
Exam code: quiz06w4VE
(A) : 39 students
(B) : 8 students
(C) : 3 students
(D) : 2 students

Success level: 74%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

Physics quiz question: mass-spring potential energy

2011-11-23T00:05:00.000-08:00

Physics 205A Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 10.13

A 0.75 kg mass attached to a horizontal spring has a 4.0 s period of oscillation. Neglect friction and drag. The velocity versus time graph for this mass-spring system is shown at right. What is the earliest time that the system will have its maximum elastic potential energy?
(A) 0 s.
(B) 1 s.
(C) 2 s.
(D) 3 s.

Correct answer: (B)

The elastic potential energy U_elas of the mass-spring system will be at a maximum when the translational kinetic energy K_tr is zero, which occurs at t = 1 s, which is the earliest time when the velocity v is zero.

Sections 70854, 70855
Exam code: quiz06w4VE
(A) : 16 students
(B) : 25 students
(C) : 11 students
(D) : 1 student

Success level: 47%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.68

Physics quiz question: changing wave source frequency

2011-11-22T00:05:00.000-08:00

Physics 205A Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Questions 11.5, 11.6

A periodic wave has a frequency and wavelength of 125 Hz and 0.60 m, respectively. If the frequency of the wave source is increased, the __________ would increase.
(A) wave speed.
(B) wavelength.
(C) (Both of the above choices.)
(D) (Neither of above choices.)

Correct answer: (D)

Wave speed v depends on the properties of the medium. Frequency f depends on the properties of the source. These two parameters can be varied independently of each other.

The wavelength λ is the parameter dependent on both of the independent parameters:

λ = v/f,

such that increasing the frequency f of a wave source will not affect the wave speed v, but will cause the wavelength λ to decrease.

Response (A) is incorrectly interpreting the mathematically correct statement:

v = λ*f,

to mean that the wave speed v depends on wavelength λ and frequency f.

Sections 70854, 70855
Exam code: quiz06w4VE
(A) : 26 students
(B) : 4 students
(C) : 0 students
(D) : 23 students

Success level: 43%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.46

Physics quiz question: frequency of standing wave on a string

2011-11-21T00:05:00.000-08:00

Physics 205A Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 11.4, Multiple-Choice Question 11.5

A viola's A-string[1],[2] has a length of 0.37 m and is stretched to a tension of 53 N. It vibrates at a fundamental frequency of 440 Hz. In order to increase the fundamental frequency of this viola string, which of the following should be done?
(A) Press a finger on the string, such that a shorter length of it vibrates.
(B) Increase the tension of the string.
(C) (Both of the above choices.)
(D) (Neither of above choices.)

[1] http://theviolaworkshop.com/page16.html
[2] http://gamutmusic.squarespace.com/viola-tensions/.

Correct answer: (C)

The fundamental frequency of a standing wave on a string is given by:

f₁ = sqrt(F/µ)/(2*L),

such that either decreasing the length L of the string, or increasing the tension F of the string would both result in an increase in f₁.

Sections 70854, 70855
Exam code: quiz06w4VE
(A) : 13 students
(B) : 13 students
(C) : 26 students
(D) : 2 students

Success level: 49%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73

Physics quiz archive: SHM, waves

2011-11-20T00:05:00.000-08:00

Physics 205A Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA
Sections 70854, 70855, version 1

Sections 70854, 70855 results
Exam code: quiz06w4VE

 0- 6 : **  [low = 6]
 7-12 : ********
13-18 : ***************
19-24 : ********************  [mean = 19.2 +/- 5.2]
25-30 : ********  [high = 30]

Overheard: recursive learning about stars

2011-11-19T00:05:00.000-08:00

Astronomy 210, fall semester 2011
Cuesta College, San Luis Obispo, CA

(Overheard at a review session just before midterm on the sun/stars/Milky Way/cosmology.)

Instructor: "Just think: you're learning about stars that died...to make the atoms...that made you...so you could learn...about the stars."

Students: (Beat.) "Whoa."

Instructor: "Yeah. Whoa."

Astronomy current events question: Phobos-Grunt mission

2011-11-18T23:11:00.000-08:00

Jonathan Amos, "Asteroid Lutetia May Have Core of Hot Melted Metal," November 9, 2011
http://www.bbc.co.uk/news/science-environment-15631472

The Russian Space Agency Phobos-Grunt spacecraft, which is experiencing technical problems, was intended to travel to Mars to:
(A) bring back a sample from one of its moons.
(B) burrow underground to search for water.
(C) produce fuel for future space missions.
(D) search for the defunct NASA Spirit rover.
(E) map the "face on Mars" with high-resolution radar.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 38 students
(B) : 8 students
(C) : 0 students
(D) : 3 students
(E) : 7 students

Astronomy current events question: asteroid 21 Lutetia

2011-11-18T23:09:00.000-08:00

Charles Q. Choi, "Asteroid Lutetia May Have Core of Hot Melted Metal," October 27, 2011
http://www.msnbc.msn.com/id/45065506/ns/technology_and_science-space#.TsdVq4BW4lZ

The __________ of asteroid 21 Lutetia measured by the European Space Agency Rosetta spacecraft may be evidence that the asteroid has a molten metal core.
(A) reflectivity.
(B) crater density.
(C) infrared emissions.
(D) density.
(E) roundness.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 0 students
(B) : 6 students
(C) : 13 students
(D) : 37 students
(E) : 0 students

Astronomy current events question: 2011 Leonid meteor shower

2011-11-18T23:06:00.000-08:00

Bill Andrews, "Get Ready for the 2011 Leonid Meteor Shower," November 8, 2011
http://astronomy.com/News-Observing/News/2011/11/Get%20ready%20for%20the%202011%20Leonid%20meteor%20shower.aspx

The Leonid meteor shower that peaks on the morning of November 18 will be expected to be muted this year because of:
(A) the end of daylight saving time.
(B) a partial lunar eclipse.
(C) intense northern light activity.
(D) light from the moon.
(E) asteroid 2005 YU55 passing by Earth earlier this month.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 1 student
(B) : 4 students
(C) : 3 students
(D) : 37 students
(E) : 11 students

Online reading assignment question: keep, quit, start

2011-11-18T00:05:00.000-08:00

Astronomy 210 Keep-Quit-Start Reading Assignment, fall semester 2011
Cuesta College, San Luis Obispo, CA

111116-astr210-keep
http://www.flickr.com/photos/waiferx/6350653663/
Originally uploaded by Waifer X

Wordle.net tag cloud for "keep" resolutions generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA, fall semester 2011 (www.wordle.net/show/wrdl/4424300/Untitled).

111116-astr210-quit
http://www.flickr.com/photos/waiferx/6351397434/
Originally uploaded by Waifer X

Wordle.net tag cloud for "quit" resolutions generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA, fall semester 2011 (www.wordle.net/show/wrdl/4424360/Untitled).

111116-astr210-start
http://www.flickr.com/photos/waiferx/6351397506/
Originally uploaded by Waifer X

Wordle.net tag cloud for "start" resolutions generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA, fall semester 2011 (www.wordle.net/show/wrdl/4424146/Untitled).

Students were asked to answer a "keep-quit-start" online reflection (hosted by SurveyMonkey.com) on their studying strategies/pitfalls (Mubayiwa, 2009).

Enter a word or brief phrase that describes what you intend to keep doing to study for this class. Explain your answer to the above question (what you intend to keep doing to study for this class).

Enter a word or brief phrase that describes what you intend to quit doing to study for this class. Explain your answer to the above question (what you intend to quit doing to study for this class).

Enter a word or brief phrase that describes what you intend to start doing to study for this class. Explain your answer to the above question (what you intend to start doing to study for this class).

[Word tags have been edited to consolidate related common subjects; student explanations are verbatim.]

Student responses
Sections 70158, 70160

Keep word tags:

effort
At the end of the day, all you can truly ask of someone is to try their best.

flashcardquestions ("peer instruction," "think-pair-share")
After not using the flashcard packets, I realized that studying them and filling them out really does improve my understanding of the subject.
I mean to keep printing out the Flash Card Notes to study them because it helps with Quizzes.
Read these through is extra review.
it really helps to study them, to help rememer what we learned in class.
Going over old quizzes and flashcard questions helps me review the material
By printing out the flashcard questions it allows me to keep on track while reading, and write down correct answers that we go over in class. This then makes it less confusing when I am trying to go back a few days and study.
Write down questions and answers from class
They give A great forecast for quizzes

gotoclass
I've found sometimes just reading from the textbook maybe dry and somewhat vague. So coming to lecture definitely helps to get a better grasp of the material.
I will keep attending class because that is where you learn everything.
Lecture helps me to better understand what I read in the book, as well as information i need clarified.
I'll keep attending class
missing a lecture sucks, cause then you have to read and be totally confused.

notes
good lecture notes help alot when studying for tests.

participate
Participating in flashcard questions and group work is essential to understanding concepts.

payattention
just pay good attention to the lecture

practiceexams
When I study old quizzes it helps me understand things better and helps me know what I should study for, for the next quiz.
Before each quiz and midterm, I will continue to review the practice quizzes to better prepare myself and be more familiar with the types of questions.

read
reading the chapters of the book
I have this really bad habit of never touching my textbooks. I should really get over it.
I am forcing myself to ingrain the habit to do all post labs, prereads, and other online assignments on one day before the start of the week.

review
In order to do well on the quizzes and midterms, I know that I need to review the information we go over every week, and study the sample questions we do in class in order to better understand the material and do well on the tests.

study
I intend to KEEP studying hard the several days before quizzes, midterm 2, and the final.
I need to keep studying, because studying is important.
I will keep reading the book no matter how hard.
I am taking notes, printing out all the flashcard questions, and continuing to study.
What else do I have to say? Always study and be prepared for any assignment or test.
It is important to get a good grade.
I read the book and I study for the midterm and read flashcard questions.
Study, and go to class
I need to study the material a little bit more to keep succeeding

studygroups
I study with another classmate and it helps quite a bit on the quizes.

Quit word tags:

cramming
Get over loaded before class

distractions
Facebook is pretty distracting especially when doing homework assignments on the computer.

doodling
I only did this once, but then I was completely confused next lecture.
getting distracted during lecture by doodling

gettingsick
i unfortunately had to walk out of class because i was coughing up a lung last session. I have been taking my Vitamin C and feel confident that I am over my cold.

lackofcaffeine
I always come straight to class after long work days, and I really need to drink more caffeine and have a more balanced meal prior to.

laziness
not be lazy and just blow off the reading assigments they're easy points

leavingearly
Staying in class for both parts of lecture is important.
I'm going to stay the whole class

missclass
i would like to go to class to get the particpation points and get the info
I will not miss any classes or homework
Whenever I miss class I miss something important.
missing a lecture sucks, cause then you have to read and be totally confused.
Not attending due to its length of class and terrifying time of class

noclue
I have no idea

nothing
There is nothing that i intend to quit doing in order to succeed in this class
If I quit, I fail.

notstudying
I will stop not studying so i do better on tests.

procrastination
Usually after class I won't look at what we went over with the idea that I'll study it later before the quiz. If I want to fully understand the material I have to review it more frequently.
When I study for a quiz at the last minute I end up being really tired for the quiz or exam and end up not doing my best.
I intend to QUIT procrastinating and study even sooner so that Sunday studying isn't so intense. It hasn't hurt my performance, but it would be less stressful and allow more time for my brain to absorb all the information.
I tend to procrastinate in classes that don't assign daily homework or papers. I intend to spend more time studying for astronomy quizzes and exams.
My worst quality!
I tend to procrastinate in every class. I should change that... but I'll probably put off breaking that habit. :[
I keep waiting until the last second to do surveys and end up forgetting. I need to do them on Thursdays or something.
Stop procrastinating when it comes to studying for quizzes and midterms.
I need to just do the reading and not wait until the night before.
i have a habit of it, i need to motivate myself to get things done earlier
I often wait until Wednesday night to do homework and study. I will try and work on Astronomy earlier in the week and more frequently
I need to start reading chapters on time

quitting
I got to quit quitting.

skippingmeals
I don't usually skip out on meals, but I like to at least have some amount of nutritious food energizing my body.

slacking
now that i have more time to focus on school, i intend to study way more for this class.
I haven't been keeping up with studying for this class (blame College Algebra for that P-Dog).

Start word tags:

ask
Most people wont ask questions in class. If I don't understand a concept I'll start raising my hand more too better understand what's going on.

caffeinate
I need more of it.

examples
I am going to analyze the examples provided in the textbook that relate to the subject(s) I need to study.

flashcardquestions ("peer instruction," "think-pair-share")
Start reading flashcard questions to see what will be on the test.
I need to do more of the flashcards
Printing out Flash Cards before class instead of after
Because a lot of the quizes and tests are just the same questions, but also since the packets cover just about everything we need to know regardless. Or at least hit the main points.
I did the flash card questions for the last midterm to help study and they helped a ton. so im gonna start dion them again.
Sending in my flash card answers so I know I am studying correctly

focus
Gotta focus on studying and reviewing as much as possible for the class; going over material and reviewing the study questions.

fullspeedahead
Don't worry so much and keep pushing for success

notes
I should probably take more notes during lecture.
take better notes during lecture
By writing group work questions down I will have more reference questions and more to study for quizzes and midterms
Write more detailed notes from lectures
A well maintained note book can make or break a grade, and i plan to always improve my note taking skills

practiceexams
These practice quizzes are really helpful because it helps you identify what you need to know for the quiz.

read
I intend to start going through the book to help me understand things better when I get lost or confused.
Reading the book is important.
From lecture and also reading the textbook it makes thing become more clear and you're able to understand the material a little better.
I will start to read the book more.
I wish I could but I can't.

research
I should look up articles relating to the questions on the survey reading, not just to get the answers to the questions, but know why the evidence supports it.

starting
Missing the easy homework points has lowered my grade, I need to start to consistently remember to complete the homework.
i need to stop procrastinating.
I need to start studying for quizzes and tests sooner in order to remember all the information

study
need to study more and pay better attention to what im studying
I intend to allocate more time to studying for this class since I know that I have neglected it compared to studying for my other classes.
Giving myself more time to study
As it gets closer to end of the semester, I need to bump up my studying to ensure that I get the grade that I want.
I will study harder for the next midterm
Study group for midterm
Going over flashcard question, reading the book for overview, and making sure I know the material beyond what I merely remember from class.

studygroup
I think it would be helpful to study with a classmate and practice quizzing each other. I think it would make studying more fun and effective.
Getting together with other students might help.

Online reading assignment question: keep, quit, start (Physics 205A, fall semester, 2011).

Online reading assignment question: keep, quit, start (Astronomy 210, spring semester, 2011).

Online reading assignment question: keep, quit, start (Astronomy 210, fall semester, 2010).

Astronomy quiz question: monolithic collapse model

2011-11-17T00:05:00.002-08:00

Astronomy 210 Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

According to the monolithic collapse model, there should be no young stars in globular clusters because:
(A) metal-rich stars in the halo have already become metal-poor stars.
(B) there are no metals left in the halo.
(C) dark matter in the halo prevents new stars from forming.
(D) interstellar hydrogen in the halo moved into the disk.

Correct answer: (D).

Since the distribution of interstellar hydrogen in the Milky Way has flattened from spherical to disk-shaped, new star formation occurs only in the disk, and not in the halo, where the first generation stars of the globular clusters are located.

Section 70160
Exam code: quiz06n4Nd
(A) : 11 students
(B) : 4 students
(C) : 2 students
(D) : 9 students

Success level: 40% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.63

Astronomy quiz question: globular star clusters

2011-11-17T00:05:00.001-08:00

Astronomy 210 Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

The locations of globular star clusters provide evidence for:
(A) dark matter in the halo.
(B) self-sustaining star formation.
(C) the Milky Way's spiral arm structure.
(D) the location of the Milky Way's center.

Correct answer: (D).

The distribution of globular clusters in the halo, above and below the disk, is used to locate the center of the Milky Way.

Section 70158
Exam code: quiz06pOp1
(A) : 2 students
(B) : 1 students
(C) : 6 students
(D) : 23 students

Success level: 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.56

Section 70160
Exam code: quiz06n4Nd
(A) : 1 student
(B) : 1 student
(C) : 6 students
(D) : 9 students

Success level: 61% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.49

Astronomy quiz question: spiral arm tracers

2011-11-17T00:05:00.000-08:00

Astronomy 210 Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Spiral arms can be traced through the sun's neighborhood by locating the positions of spiral tracers such as:
(A) Cepheid variable stars.
(B) globular clusters.
(C) type Ia and type II supernovae.
(D) massive stars.

Correct answer: (D).

Massive stars are luminous and short-lived, so they only be located near where they were born from a spiral arm density wave. Cepheid variable stars are used to determine the distances to globular clusters in the halo of the Milky Way, and the distribution of globular clusters is used to locate the center of the Milky Way. Observations of type Ia and type II are used to determine the distances to other galaxies.

Section 70158
Exam code: quiz06pOp1
(A) : 9 students
(B) : 11 students
(C) : 4 students
(D) : 7 students
(No response: 1 student)

Success level: 27% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): -0.13

Astronomy quiz archive: Milky Way, cosmology

2011-11-16T08:23:00.001-08:00

Astronomy 210 Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz06pOp1

Section 70158

Quiz 6 results (max score = 40):
   0- 8.0 : *  [low = 7.5]
 8.5-16.0 : ****
16.5-24.0 : **************  [mean = 22.8 +/- 6.6]
24.5-32.0 : **********
32.5-40.0 : ***  [high = 36.5]

Astronomy quiz archive: Milky Way, cosmology

2011-11-16T08:20:00.000-08:00

Astronomy 210 Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA

Section 70160, version 1
Exam code: quiz06n4Nd

Section 70160

Quiz 6 results (max score = 40):
   0- 8.0 : *  [low = 6.0]
 8.5-16.0 : **
16.5-24.0 : ****
24.5-32.0 : **********  [mean = 27.4 +/- 9.0]
32.5-40.0 : *********  [high = 40.0]