Online reading assignment question: Milky Way tags

Astronomy 210 Reading Assignment 10, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

101031-milkywaywordle
http://www.flickr.com/photos/waiferx/5134430271/
Originally uploaded by Waifer X

Wordle.net tag cloud for "Milky Way," generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/2655733/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.

Write down five words that describe or are associated with the "Milky Way." Keep word phrases together with no spaces between them (e.g., "forexample, likethis, nospaces"). (Graded for completion.)

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

Student responses
Sections 70158, 70160

:)
100000lightyearsaway
100billionsolarmasses
13billionyearsold
13billionyearsold
13billionyearsold
200-400billionsofstars
abandoffaintstarsacrossthecelestialsphere
amazing
arm
astrological
astronomical
atoms
awesome
awesome
awesome
band
band
bandoflight
bandoflight
bar
bar
barred
barredspiral
barredspiral
beautiful
beautiful
belt
big
big
big
big
big
big
bigspace
billion
blackhole
blackhole
blackholeatcenter
branches
bright
bright
bright
candy
candy
candy
candy
candy
candy
candybar
candybar
candybar
candybar
candybar
candybar
cannibal
caramel
caramel
caramel
caramel
caramel
celestialsphere
celestialsphere
Cepheidvarablestars
chewy
chocolate
chocolate
chocolate
chocolate
chocolate
chocolate
chocolate
chocolate
chocolate
chocolate
chocolate
clumpofstars
cluster
cluster
clusters
complex
concentration
cows
creamy
creamy
creamy
crowded
crowded
darkchocolateisbetter
deliciousness
deliciousness
densitywavetheory
disc
discoveredbyDemocritus
disk
disk
disk
diskcomponent
diskshape
dust
dust
dust
dustclustered
Earth
earth
earth
emissionnebula
encompassing
expansive
faint
faint
farout
flowinggases
fluffy
galactic
galaxies
galaxies
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxy
galaxywherethesolarsystemlives
gammarays
gas
gas
gas
gigantic
globularclusters
globularclusters
globularclusters
globularclusters
glow
good
gravity
GreatRift
halo
halo
halo
halo
halopopulationstars
HarlowShapley
hazy
home
home
huge
huge
huge
huge
hydrogen
Idontknow
Imnotlateyet
incredible
instability
interstellar
interstellarmedium
invisiblecosmicrays
kiloparsec
kuklos
life
light
light
lightyears
lightyears
line
little
locatednearSagittarius
long
lotofstars
magnificent
manystars
mass
massive
MeninBlack
metals
metals
milk
milky
milky
milky
milkycircle
millionsofstars
monolithiccollapsemodel
monolithiccollapsemodel
monolithiccollapsemodel
monolithiccollapsemodel
monolithiccollapsemodel
moons
night
NorthernCross
nougat
nougat
nova
nuclearbulge
nuclearbulge
nuclearbulge
nuclearbulge
nucleus
old
openclusters
ourgalaxy
oursolarsystem
overwhelming
planets
planets
planets
planets
planets
planets
planets
planets
population
populationIIstars
populationIIstars
populationIstars
populationIstars
pretty
pretty
pretty
pretty
propermotions
rocks
rotation
SagittariusA
snickers
solarsystem
solarsystem
solarsystem
solarsystem
solarsystem
solarsystem
space
spacedust
spacey
sphericalcomponent
sphericalcomponent
spiral
spiral
spiral
spiral
spiral
spiral
spiral
spiral
spiral
spiral
spiral
spiral
spiralarm
spiralarms
spiralarms
spiralarms
spiralarms
spiralarms
spiralarms
spiralgalaxy
spiralgalaxy
spiralshape
spiraltracers
spurs
starclusters
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
stars
SummerTriangle
suns
superawesomeness
supermassiveblackhole
system
technical
thisisweird
trail
typeIIsupernova
universe
universe
universe
unseen
vast
verycold
verydark
vialactea
vialactea
wheelshaped
whirlpool
whitestripe
WilliamandCarolineHerschel
yummy
yummy
yummy
yummy

Astronomy quiz question: most luminous stars?

Astronomy 210 Quiz 5, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Which type of main-sequence star is the most luminous?
(A) Low mass (red dwarf).
(B) Medium-mass (sunlike).
(C) Massive.
(D) (This property does not depend on mass.)

Correct answer: (C)

This can be deduced from either the mass-luminosity relationship (luminosity proportional to (mass)^3.5), or by inspection of an H-R diagram, where the upper-left end of the main sequence represents hot, bright, massive stars.

Section 70160
(A) : 1 student
(B) : 1 student
(C) : 31 students
(D) : 1 student

"Success level": 92% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.78

Physics quiz question: comparing potential differences in parallel circuit

Physics 205B Quiz 4, fall semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 18.21

An ideal 8.0 V emf source is connected to a 1.5 Ω resistor and a 15.5 Ω light bulb. The __________ has the greater potential difference.
(A) 1.5 Ω resistor.
(B) 15.5 Ω light bulb.
(C) (There is a tie.)
(D) (Not enough information is given.)

Correct answer (highlight to unhide): (C)

Kirchhoff's loop rule can be applied to either a complete loop that incorporates the 8.0 V emf with the 1.5 Ω resistor, or another complete loop that incorporates the 8.0 V emf with the 15.5 Ω resistor. As the potential rises and drops in a complete loop must sum to zero, then the potential difference across the 1.5 Ω resistor must be 8.0 V; and the potential difference across the 15.5 Ω resistor must be 8.0 V as well. (This is a consequence of these resistors being connected in parallel to the emf.)

Student responses
Section 70856
(A) : 1 student
(B) : 6 students
(C) : 4 students
(D) : 0 students

Success level: 36%
Discrimination index (Aubrecht & Aubrecht, 1983): 1.00

Physics quiz question: sound system capacitor

Physics 205B Quiz 4, fall semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 17.73(b)

"C22_MAIN.JPG"
Sound System Laboratories
soundstormlab.com/auto/car-audio-sound-system-auto-stereo-capacitor-farad-sound-storm-c22/

A Sound Storm Laboratories C22 car audio system capacitor[*] stores 400 J of energy when it holds 40 C of charge. The potential difference across the capacitor is:
(A) 5.0 V.
(B) 10 V.
(C) 20 V.
(D) 8.0×10³ V.

[*] soundstormlab.com/auto/car-audio-sound-system-auto-stereo-capacitor-farad-sound-storm-c22/.

Correct answer (highlight to unhide): (C)

The electric potential energy in a capacitor is given by EPE = (1/2)·Q·∆V, such that:

∆V = 2·EPE/Q = 2·(400 J)/(40 C) = 20 J/C = 20 V.

(Response (A) is (1/2)·(EPE/Q); response (B) is EPE/Q; response (C) is (1/2)·EPE·Q.)

Student responses
Section 70856
(A) : 0 students
(B) : 4 students
(C) : 7 students
(D) : 0 students

Success level: 63%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.42

Physics quiz question: different gap capacitors

Physics 205B Quiz 4, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 17.55

Two parallel plate capacitors have the same area, and same charge, but different separation gaps. The parallel plate capacitor with the ___________ separation gap has a greater potential difference.
(A) wider.
(B) narrower.
(C) (There is a tie.)
(D) (Not enough information is given.)

Correct answer: (A)

Both capacitors have the same area, but different separation gaps. The wider separation gap capacitor will have the smaller capacitance, as seen from:

C = A/(4*pi*k*d).

Both capacitors have the same charge. So the wider separation gap capacitor, having the smaller capacitance, will have the greater potential difference as seen from:

delta(V) = Q/C = Q/(A/(4*pi*k*d)) = 4*pi*k*Q*d/A = (4*pi*k*Q/A)*d.

Student responses
Section 70856
(A) : 8 students
(B) : 3 students
(C) : 0 students
(D) : 0 students

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

Physics quiz question: separating opposite charges

Physics 205B Quiz 4, fall semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Questions 17.1, 17.4, 17.6

A –12 µC source charge is held at the origin, and a +2.0 µC test charge is at x = +4.0 cm. As it is moved from x = +4.0 cm to x = +5.0 cm, the +2.0 µC test charge moves to a region of __________ potential, while its potential energy __________.
(A) lower; decreases.
(B) lower; increases.
(C) higher; decreases.
(D) higher; increases.

Correct answer (highlight to unhide): (D)

The potential of the –12 µC source charge is given by:

V = k·(–12×^-6 C)/r,

so increasing r (relocating from x = +4.0 cm to +5.0 cm) would make the potential a smaller negative number, which means moving to a region of higher potential.

The electrical potential energy of the two charges is given by:

EPE = k·(-12×10^–6 C)·(+2.0×10^–6 C)/r,

so increasing r (moving the +2.0 µC test charge from x = +4.0 cm to +5.0 cm) would make the electric potential energy a smaller negative number, as well, which means it increases.

Student responses
Section 70856
(A) : 2 students
(B) : 5 students
(C) : 0 students
(D) : 4 students

Success level: 36%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

Astronomy quiz question: apparent vs. absolute magnitude

Astronomy 210 Quiz 4, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

Fomalhaut is a star that is located 7.7 parsecs away from Earth. If Fomalhaut were moved to a location 10 parsecs away, its apparent magnitude m would __________, while its absolute visual magnitude M_V would __________.
(A) get dimmer; not change.
(B) get brighter; not change.
(C) not change; get dimmer.
(D) not change; get brighter.

Correct answer: (A)

The apparent magnitude of Fomalhaut, which is the brightness as seen from Earth, will get dimmer as it is moved farther away from 7.7 parsecs to 10 parsecs. The absolute visual magnitude, which is the intrinsic brightness, will remain the same no matter where Fomalhaut is located.

Section 70158
(A) : 33 students
(B) : 0 students
(C) : 8 students
(D) : 2 students

"Success level": 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.75

[Version 2]

Antares is a star that is located 190 parsecs away from Earth. If Antares were moved to a location 10 parsecs away, its apparent magnitude m would __________, while its absolute visual magnitude M_V would __________.
(A) get dimmer; not change.
(B) get brighter; not change.
(C) not change; get dimmer.
(D) not change; get brighter.

Correct answer: (B)

The apparent magnitude of Antares, which is the brightness as seen from Earth, will get brighter as it is moved closer from 190 parsecs to 10 parsecs. The absolute visual magnitude, which is the intrinsic brightness, will remain the same no matter where Antares is located.

Section 70160
(A) : 4 students
(B) : 28 students
(C) : 1 students
(D) : 8 students

"Success level": 70% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73

Astronomy quiz question: parallax angle and parsecs

Astronomy 210 Quiz 4, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Proxima Centauri is a star that has a parallax angle just a little smaller than 1 arcsecond. Approximately how far away is Proxima Cenaturi?
(A) Much farther away than 1 parsec.
(B) A little farther away than 1 parsec.
(C) Exactly 1 parsec away.
(D) Closer than 1 parsec away.

Correct answer: (B)

A star that is exactly 1 parsec away would have a parallax angle of 1 arcsecond. A closer star would have a larger parallax angle. With a parallax angle slightly smaller than 1 arcsecond, the star would be slightly farther away than 1 parsec. (A star with a parallax angle much smaller than 1 arcsecond would be much farther away than 1 parsec.)

Section 70158
(A) : 10 students
(B) : 15 students
(C) : 2 students
(D) : 18 students

"Success level": 39% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.08

Section 70160
(A) : 2 students
(B) : 13 students
(C) : 4 students
(D) : 22 students

"Success level": 38% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.36

Astronomy quiz question: Procyon B vs. Barnard's Star, Rigel B vs. Arcturus

Astronomy 210 Quiz 4, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

Procyon B, a white dwarf, has the same luminosity as Barnard's Star, a red dwarf. Procyon B is ___________ compared to Barnard's Star.
(A) smaller and cooler.
(B) smaller and hotter.
(C) larger and cooler.
(D) larger and hotter.

Correct answer: (B)

From Wien's law and/or using an H-R diagram, Procyon B (white dwarf) must be hotter than Barnard's Star (red dwarf). In order to have the same luminosity, from the Stefan-Boltzmann law, Procyon B must be smaller in size to compensate for its higher temperature, compared to Barnard's Star, which must be larger in size to compensate for its lower temperature.

Section 70158
(A) : 1 student
(B) : 35 students
(C) : 3 students
(D) : 6 students

"Success level": 79% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.42

[Version 2]

Rigel B, a blue-hot star, has the same luminosity as Arcturus, a yellow-hot star. Rigel B is ___________ compared to Arcturus.
(A) cooler and smaller.
(B) cooler and larger.
(C) hotter and smaller.
(D) hotter and larger.

Correct answer: (C)

From Wien's law, Rigel B (blue-hot) must be hotter than Arcturus (yellow-hot). In order to have the same luminosity, from the Stefan-Boltzmann law, Rigel B must be smaller in size to compensate for its higher temperature, compared to Arcturus, which must be larger in size to compensate for its lower temperature.

Section 70160
(A) : 0 students
(B) : 1 student
(C) : 34 students
(D) : 6 students

"Success level": 85% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.18

Astronomy current events question: Gliese 581g non-existent?

Astronomy 210L, Fall Semester 2010
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!)

Rachel Courtland, "First Life-Friendly Exoplanet May Not Exist," October 13, 2010
http://www.newscientist.com/article/dn19586-first-lifefriendly-exoplanet-may-not-exist.html

The evidence for the recent discovery of "potentially habitable" planet Gleise 581g has been called into question by another research group because of:
(A) analysis of slightly different data sets.
(B) accusations of academic misconduct.
(C) glitches in computer programs used.
(D) the extremely short lifetime of the star Gliese 581.
(E) periodic solar flares from the star Gliese 581.

Correct answer: (A)

Student responses
Sections 70178, 70186, 70200
(A) : 48 students
(B) : 2 students
(C) : 1 student
(D) : 2 students
(E) : 5 students

Astronomy current events question: Dawn spacecraft and Hubble Space Telescope

Astronomy 210L, Fall Semester 2010
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!)

Astronomy.com editors, "Mission to Asteroid Gets Help from Hubble Space Telescope," October 11, 2010
http://www.astronomy.com/asy/default.aspx?c=a&id=10304

The NASA Dawn spacecraft needs the Hubble Space Telescope to observe the asteroid Vesta in order to:
(A) avoid colliding with it while passing through the asteroid belt.
(B) fly by when sunlight can illuminate certain features on it.
(C) plan a landing somewhere on its equator.
(D) warn of possible volcanic eruptions on its surface.
(E) update its position, as the Dawn spacecraft is "flying blind."

Correct answer: (B)

Student responses
Sections 70178, 70186, 70200
(A) : 9 students
(B) : 24 students
(C) : 7 students
(D) : 2 students
(E) : 14 students

Astronomy current events question: "The Year of the Solar System"

Astronomy 210L, Fall Semester 2010
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!)

Dr. Tony Phillips, "The Year of the Solar System," October 7, 2010
http://science.nasa.gov/science-news/science-at-nasa/2010/07oct_yss/

NASA has announced that October 2010 through August 2012 will be "The Year of the Solar System," when:
(A) the sun lines up with the center of the Milky Way.
(B) planets are nearly aligned in a straight line.
(C) planets have the same configuration as during Galileo's time.
(D) a large number of spacecraft arrive at their destinations.
(E) a different planet is visible almost each and every night.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 3 students
(B) : 2 students
(C) : 1 student
(D) : 48 students
(E) : 4 students

Astronomy midterm question: SOFIA infrared observing options?

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

[20 points.] NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5 m diameter reflecting telescope mounted on a converted Boeing 747 aircraft that will make infrared observations in the upper atmosphere. Discuss whether this is the best option, compared to a space-based infrared telescope of similar size. Explain the reasoning behind your decision, in terms of cost-effectiveness and light-gathering ability.

(Image credit: "ED10-0080-03," NASA/Jim Ross, 
http://www.nasa.gov/centers/dryden/multimedia/imagegallery/SOFIA/ED10-0080-03.html.)

Solution and grading rubric:

• p = 20/20:
  Correct. In general, the atmosphere is not transparent to infrared, such that both a high-altitude airplane-borne telescope and a space-based telescope will be able to make observations. Since an airplane-borne telescope is cheaper than a space-based telescope, the airplane-borne telescope should be funded. (Or may want to fund the space-based telescope if plausible arguments for why flying an airplane continuously would be more expensive than placing a telescope in orbit, or having stability, continuous observing, or absolutely no atmospheric absorption would be paramount.)
  
• 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. Does not specifically discuss the relative transparency of Earth's atmosphere to infrared, but only in general terms such as disruption, inteference, distortion.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Decision based on other considerations such accessibility and cost, without mention of atmospheric effects.
  
• 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
p: 37 students
r: 2 students
t: 8 students
v: 3 students
x: 1 students
y: 0 students
z: 1 student

A sample "p" response (from student 4117):


[Version 2]

[20 points.] NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5 m diameter reflecting telescope mounted on a converted Boeing 747 aircraft that will make infrared observations in the upper atmosphere. Discuss whether this is the best option, compared to a ground-based infrared telescope of similar size. Explain the reasoning behind your decision, in terms of cost-effectiveness and light-gathering ability.

(Image credit: "ED10-0080-03," NASA/Jim Ross, 
http://www.nasa.gov/centers/dryden/multimedia/imagegallery/SOFIA/ED10-0080-03.html.)

Solution and grading rubric:

• p = 20/20:
  Correct. In general, the atmosphere is not transparent to infrared, such that a ground-based infrared telescope would not be able to make observations, while a high-altitude airplane-borne telescope, or a space-based telescope will be able to make observations. Thus a ground-based infrared telescope (assuming at sea level or a relatively low elevation), while being cheaper than an airplane-borne telescope, would be ineffective and thus should not be funded. (Or may want to fund the "ground-based" telescope if placed on top of a high-enough mountain.)
  
• 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. Does not specifically discuss the relative transparency of Earth's atmosphere to infrared, but only in general terms such as disruption, inteference, distortion.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• 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 70160
p: 34 students
r: 2 students
t: 1 student
v: 0 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1958):

Astronomy midterm question: implausible moonrise?

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

[20 points.] Consider the following excerpt describing the rising of a crescent moon:

The sun sank and the world was wreathed in shadows. But not for long, for see, in the east there is a glow...and at last the full bow of the crescent moon peeps above the plain...
--H. Rider Haggard, King Solomon's Mines: A Novel, Longmans, Green and Co., 1901, pp. 114-115.

Decide whether seeing a crescent moon rising soon after sunset is plausible or implausible. Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer.

Solution and grading rubric:

• p = 20/20:
  Correct. Waning crescent moon rises at 3 AM (also the waxing crescent moon rises at 9 AM), so it cannot rise (in the east) soon after sunset, as it will already be in the west part of the sky. May instead discuss that a waning gibbous moon (or full moon) would rise soon after sunset.
  
• 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. Problems with either diagram, phase, or time, but at least attempts to argue implausibility based on restrictions on when moon phase is visible or not visible.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Problems with diagram, phase, and time.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit. Explanation based on eclipses, solstices, etc.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 70158
p: 19 students
r: 4 students
t: 8 students
v: 7 students
x: 7 students
y: 2 students
z: 0 students

A sample "p" response (from student 7734):

Another sample "p" response (from student 1986):

Astronomy midterm question: orbital eccentricity as reason for the seasons?

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

[20 points.] A Harvard undergraduate student was interviewed just after his commencement ceremony to explain the causes of the seasons:

I think the seasons happen because as Earth travels around the sun, it gets nearer to the sun, which produces warmer weather, and [Earth] gets farther away [from the sun] which produces colder weather.
--A Private Universe, Science Media Group, Harvard University/Smithsonian Institution, Cambridge, MA (1989), http://www.youtube.com/watch?v=p0wk4qG2mIg.

With the assumption that this explanation is correct, discuss the type of seasons that an observer in San Luis Obispo, CA (above the equator) will experience compared to an observer in Sydney, Australia (below the equator). Support your answer using a diagram showing the positions of the sun, Earth, and observers above and below the equator.

Solution and grading rubric:

• p = 20/20:
  Correct. Discusses that if the variation in sun-Earth distance is the cause of seasons (regardless of tilt), then SLO and Sydney will essentially experience the same seasons at the same time.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Some discussion of the student's assertion that distance is the cause of seasons, but emphasis on disproving student's assertion rather than on discussion of the seasons resulting from if the assertion were true. May have minor errors or inclusion of unrelated factors.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Explains (correctly with a diagram) how Earth's tilt causes SLO and Sydney to have opposite seasons, but does not discuss the type of seasons that SLO and Sydney will experience if the student's assertion that distance is the cause of seasons is true.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. As (t), but diagram or explanation of the effect of tilt on seasons is problematic.
  
• 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
p: 18 students
r: 5 students
t: 19 students
v: 5 students
x: 0 students
y: 0 students
z: 0 students

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

A sample "t" response (from student 1134):

Astronomy quiz question: telescope funding proposals

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

(Electromagnetic spectrum provided on Midterm 1, with transparency of Earth's atmosphere indicated for different forms of light. Downward lengths of gray bars indicates amount transmitted through atmosphere.)


Based on being able to detect its wavelength, and cost of location, which telescope should be funded?
(A) An x ray detector in space.
(B) A visible light telescope on an aircraft.
(C) A far infrared telescope in Antarctica.
(D) A radio telescope in the mountains of Chile.

Correct answer: (A)

Due to the opacity of the atmosphere, far infrared cannot be detected at ground level, eliminating choice (C). Both visible light and radio waves can be detected at ground level, so choices (B) and (D), while functional, would be unnecessarily expensive. Response (A) is the best answer because x rays cannot be detected unless a detector is in the upper atmosphere or in space, and there is no cheaper location that it would still be functional.

Section 70158
(A) : 17 students
(B) : 7 students
(C): 1 student
(D): 19 students

Success level: 40% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.42

Section 70160
(A) : 22 students
(B) : 1 student
(C): 4 students
(D): 10 students

Success level: 59% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): -0.21

Previous post:

• Astronomy quiz question: telescope funding proposals
  (Fall semester, 2009).

Astronomy midterm question: sun-sign astrology

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Earth's __________ causes the sun to appear in front of certain zodiac constellations at different times of the year.
(A) rotation.
(B) revolution.
(C) precession.
(D) tilt.
(E) (More than one of the above choices.)

Correct answer: (B)

Due to Earth's revolution around the sun, the Earth-sun line will point towards different zodiac constellations on the celestial sphere.

Section 70158
(A) : 9 students
(B) : 28 students
(C) : 5 students
(D) : 2 students
(E) : 3 students

Success level: 64% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.70

Astronomy midterm question: morning star Saturn?

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

[20 points.] Consider a popular online search (wordnetweb.princeton.edu) result for the definition of "morning star":

A planet (usually Venus) seen just before sunrise in the eastern sky.
--http://wordnetweb.princeton.edu/perl/webwn?s=morning%20star

Discuss whether it is possible or impossible for Saturn to also be a morning star, under this definition. Support your answer using a diagram showing the positions of the sun, Saturn, Earth, and an observer on Earth.

Solution and grading rubric:

• p = 20/20:
  Correct. Discusses the possibility of Saturn being in the eastern sky just before (or at) sunrise by drawing a heliocentric diagram with Saturn orbit larger than Earth's orbit, with Saturn near the opposite side of the sun (i.e., just after Earth and Saturn at conjunction), making Saturn visible to a morning observer, (slightly) higher above the same horizon as the rising sun.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Draws Saturn at or just past conjunction, which would place it low in the eastern horizon at sunrise, but claims impossible to see due to brightness of the sun, or generally indicates where Saturn must be located along its orbit to be visible at sunrise, but does not sufficiently place near the eastern horizon.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Argues possibility or impossibility based on a diagram showing Saturn visible in the western horizon at sunrise, or visible in the eastern horizon at sunset.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Problematic diagram with Earth's orbit inside of Venus, Saturn's orbit inside of Earth's.
  
• 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 70160
p: 33 students
r: 1 student
t: 3 students
v: 3 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 3363):

Astronomy current events question: retrograde planet in binary star system

Astronomy 210L, Fall Semester 2010
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!)

Alisdair Wilkins, "Retrograde Planets Could Survive Around Binary Stars," October 5, 2010
http://www.wired.com/wiredscience/2010/10/retrograde-binary-system/

University of Texas-Arlington researchers have proposed that a planet orbits a primary star in the opposite direction of its binary star companion, based on observations of the stars':
(A) reflected light.
(B) gravitational wobbles.
(C) eclipses.
(D) parallax.
(E) surrounding dusty disk gaps.

Correct answer: (B)

Student responses
Sections 70178, 70186, 70200
(A) : 2 students
(B) : 26 students
(C) : 2 students
(D) : 0 students
(E) : 1 student

Astronomy current events question: Gliese 581g

Astronomy 210L, Fall Semester 2010
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!)

Alan MacRobert, "'Potentially Habitable' Planet Found," September 29, 2010
http://www.skyandtelescope.com/news/104031014.html

The "potentially habitable" planet Gliese 581g orbiting a red dwarf star was discovered by observing the star's:
(A) reflected light.
(B) gravitational wobbles.
(C) eclipses.
(D) parallax.
(E) surrounding dusty disk gaps.

Correct answer: (B)

Student responses
Sections 70178, 70186, 70200
(A) : 0 students
(B) : 19 students
(C) : 2 students
(D) : 1 student
(E) : 2 students

Astronomy current events question: Pan-STARRS telescope

Astronomy 210L, Fall Semester 2010
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!)

Astronomy.com editors, "Pan-STARRS Discovers Its First Potentially Hazardous Asteroid," September 28, 2010
http://www.astronomy.com/asy/default.aspx?c=a&id=10273

The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) PS1 telescope is designed to detect:
(A) supernova neutrino emissions.
(B) asteroids that may impact Earth.
(C) solar flare disruptions.
(D) rapidly moving comets.
(E) space junk in low Earth orbit.

Correct answer: (B)

Student responses
Sections 70178, 70186, 70200
(A) : 1 student
(B) : 55 students
(C) : 2 students
(D) : 6 students
(E) : 0 students

Astronomy midterm question: Orion, day after Thanksgiving?

Astronomy 210 Midterm 1, fall semester 2010
Cuesta College, San Luis Obispo, CA

Shown at right is a comic strip[*] printed on November 23, 2007 (the day after Thanksgiving). Discuss a plausible time for an observer in San Luis Obispo, CA to see the constellation Orion in the night sky on this date, or discuss why this comic strip is not plausible. Defend your answer by clearly explaining how you used your starwheel to do this, along with any assumptions that you may have made.

[*] Mark Parisi, Off the Mark, United Feature Syndicate, Inc., November 23, 2007, 
http://www.offthemarkcartoons.com/cartoons/2007-11-23.gif

Solution and grading rubric:

• p = 20/20:
  Correct. Clearly explains that Orion's belt is visible on November 23 from 8 PM to 8 AM, which would make it visible throughout the entire night (most likely while highest overhead near 1 AM, as the observers are lying down looking upwards), making this comic strip plausible.
  
• 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.
  
• 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 70160
p: 33 students
r: 1 student
t: 3 students
v: 3 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 2421):

Physics midterm problem: total electric field of two fixed source charges

Physics 205B Midterm 1, fall semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 16.29

[20 points.] Consider two point charges held at fixed locations. A –8.0 nC charge is at the origin, and a second +3.5 nC charge is at x = +0.20 m. Determine whether the direction of the electric field at x = +0.40 m points to the left or to the right, 
or has no direction (if the electric field magnitude is zero.) Show your work and explain your reasoning.

Solution and grading rubric:

• p = 20/20:
  Correct. Determines directions of the electric fields of each charge separately at x = +0.40 m, where E_{-8.0 nC} points to the left, and E_{+3.5 nC} points to the right. Finds the magnitudes of these electric fields, and since E_{+3.5 nC} has a greater magnitude than E_{-8.0 nC}, the resulting total electric field at x = +0.40 m will point to the right (with a magnitude that is the arithmetic difference of the two magnitudes).
  
• r = 16/20:
  Nearly correct, but includes minor math errors. Does not clearly show the directions for each electric field, or decimal place 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.
  
• 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:
Section 70856
p: 7 students
r: 3 students
t: 0 students
v: 0 students
x: 0 students
y: 1 student
z: 0 students

A sample "p" response (from student 8110):

Education research: partial credit for multiple-choice questions (PCMC) student attitudes (Fall semester 2010)

Starting Fall semester 2008 and continuing through Fall semester 2010, Cuesta College students taking Astronomy 210 (introductory astronomy) at Cuesta College, San Luis Obispo, CA have piloted the use of partial credit for multiple-choice (PCMC) questions.

During the ninth week of instruction (after taking four multiple-choice question quizzes, and a midterm with multiple-choice questions and short-answer/essay questions), students were given the opportunity to evaluate PCMC in an online "Partial Credit for Multiple-Choice (PCMC) Survey" hosted by SurveyMonkey.com.

These are the complete survey results. Analysis will be forthcoming after more data has been compiled from future semesters. Values for the mean and standard deviations are given next to the modal response category for each question. Note that the order of questions within sections II and III were randomly scrambled for each student.

Partial Credit for Multiple-Choice Survey
Cuesta College
Astronomy 210 Fall Semester 2010 sections 70158, 70160
(N = 45)

I. In order to receive credit for completing this survey, 
   first enter your first and last name below:
   ____


II. Recall that for this semester there is PCMC = "partial 
    credit for multiple choice," where you can get partial 
    credit even after circling a wrong answer, if you have 
    also eliminated an incorrect answer by marking it with 
    an "x."      
      Answer the following statements which may or may not 
    describe your beliefs about PCMC in this class.      
      Because of PCMC...

II.1 ...I read questions more carefully.
1. Strongly disagree      0 : 
2. Disagree               0 : 
3. Neutral               11 : ***********
4. Agree                 24 : ************************  [4.0 +/- 0.7]
5. Strongly agree        10 : **********
     
II.2 ...I spend more time taking a test. 
1. Strongly disagree      2 : **
2. Disagree              14 : **************
3. Neutral               10 : **********  [3.1 +/- 1.1]
4. Agree                 15 : ***************
5. Strongly agree         4 : ****

II.3 ...I feel more confident about circling a correct choice.
1. Strongly disagree      0 : 
2. Disagree               1 : *
3. Neutral               13 : *************
4. Agree                 24 : ************************  [3.8 +/- 0.7]
5. Strongly agree         7 : *******

II.4 ...I look for incorrect choices before circling a correct choice.
1. Strongly disagree      1 : *
2. Disagree               6 : ******
3. Neutral               10 : **********
4. Agree                 21 : *********************  [3.6 +/- 1.0]
5. Strongly agree         7 : *******

III. Answer the following statements which may or may not describe 
     your beliefs about PCMC in this class.  

III.1 PCMC helped me answer test questions better.
1. Strongly disagree      0 : 
2. Disagree               1 : *
3. Neutral               17 : *****************
4. Agree                 21 : *********************  [3.7 +/- 0.7]
5. Strongly agree         6 : ******

III.2 I would recommend using PCMC in future semesters of this class.   
1. Strongly disagree      0 : 
2. Disagree               0 : 
3. Neutral                1 : *
4. Agree                 27 : ***************************  [4.4 +/- 0.5]
5. Strongly agree        17 : *****************

III.3 Having PCMC a positive experience.
1. Strongly disagree      0 : 
2. Disagree               0 : 
3. Neutral                4 : ****
4. Agree                 32 : ********************************  [4.1 +/- 0.5]
5. Strongly agree         9 : *********

III.4 Using PCMC was difficult.    
1. Strongly disagree     19 : *******************  [1.7 +/- 2.8]
2. Disagree              22 : **********************
3. Neutral                3 : ***
4. Agree                  1 : *
5. Strongly agree         0 : 

III.5 I would identify incorrect choices even without PCMC.  
1. Strongly disagree      1 : *
2. Disagree               5 : *****
3. Neutral               17 : *****************
4. Agree                 17 : *****************  [3.4 +/- 0.9]
5. Strongly agree         5 : *****

IV. (Optional.)  Please type in any comments you may have regarding 
    the use of PCMC in this class.

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

"I think it's a nice way to get at least some credit, even if you don't know the answer for sure."

"I don't think using PCMC necessarily helped me answer any questions better or improved my test taking skills, but it is really nice to get that partial credit which I think is the most positive outcome of using it. Its really hard sometimes on the quizzes because each question is worth so many points so if you get even one wrong, it drops your grade a lot. So having the option and opportunity for extra points helps a lot."

"It can cause confusion."

"I like the idea of still being able to get some credit for knowing which answers aren't correct, even if you might not get the right answer."

"I like knowing that even if I answer a question wrong I have a chance of recieving credit for the amount of inforation that I 'do' know."

"I think it is useful because even if you don't get the answer right you can cross out one's you know that are wrong."

"I think it is helpful to look out for wrong answers which can move you towards the right answer if you are unsure of the right answer."

"I think PCMC is a very fair way of grading tests. You are a least rewarded for identifying the wrong answer"

"none"

"I like it....a lot."

"like it :)"

"Great Job P-DAWGGGG!!!!!"

"I think its nice because its makes you feel better. 0 points for a question just sucks!"

"PCMC makes you feel more confident after taking a test knowing you get at least some credit for knowing a wrong answer"

"What made you choose PCMC?"

"Its a good way to receive partial credit even if you dont know the correct answer"

"I like this idea, it reinforces the fact that even though you do not know the correct answer, you still have an idea about what it could (or could not) be."

"I think it is a good idea because even if a student gets the wrong answer they can prove that know a little about subject by crossing out an answer they know is FOR SURE not correct (and the fact that partial credit is offered proves that underneath all that thuggish roughness P-dawg has a kind heart)"

"It helps, but it makes you think a little harder than you would normally."

"I like the PCMC because it helps acknowledge that i do know enough about the question to eliminate answers that are wrong and i can get a little credit for that."

"I just had trouble with figuring out how it works in the beginning--that we have to pick the correct answer AND cross out one incorrect answer---I thought at first that if you dont know the answer, you can cross out the one that is definitely incorrect..."

"Even though credit is minimal for PCMC it's still satisfying to earn that extra half point! haha"

"I really liked PCMC. They really help."

"I love PCMC!!"

"Good system, adds a little bit of wiggle-room and forgiveness on tests and quizes."

"i love it"

"I appreciate the partial credit for multiple choice because it helps improve my grade on quizzes/exams."

"From my experience with PCMC, it works fine because its partial credit that you can earn even if you get a question wrong. "

"With that you have a better chance of earning partial credit along with the points for the correct answer if one answers the correct answer"

"PCMC is good for partial credit on multiple choice questions, but it hasn't really helped me answer questions any easier. Usually its really easy to eliminate one choice anyway."

"Receiving partial credit for eliminating an obviously wrong answer is a great idea, and should be implemented more often. It's almost a form of reverse learning, in which we can identify what is at least closer to correct when throwing out one answer, and I like that. PCMC gives a student the opportunity to reinforce their own mental process of elimination, and answer things more confidently."

"in the beginning it sometimes throws you off."

"its a really good idea i wish more classes used this"

"i think the PCMC almost makes the tests too easy, because even when i get an answer wrong i get points which allows me to get a much higher grade than i normally would have."

"It's a nice safety net of sorts if you miss something while studying for a test/quiz"

"It's a great way for students to learn better by identifying and using process of elimination to get closer to the answers."

"I like having the opportunity to be able to get partial credit for a wrong answer."

"I think we should get at least a full point for pcmc instead of only half a point."

Previous posts:

• Education research: partial credit for multiple-choice questions (PCMC) student attitudes (Spring semester 2010)
Education research: partial credit for multiple-choice questions (PCMC) student attitudes (Fall semester 2008)
• Education research: partial credit for multiple-choice questions (PCMC) bibliography

Physics midterm problem: two-lens system

Physics 205B Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 24.1

[20 points.] An upright object is placed 10.0 cm to the left of a diverging lens with focal length –15.0 cm. A second converging lens with focal length +8.0 cm is to be placed to the right of the first lens. What is the minimum separation distance (in cm) between the first lens and second lens such that the second lens will be able to produce a real final image? Show your work and explain your reasoning.

Solution and grading rubric:

• p = 20/20:
  Correct. Determines that the first diverging lens will produce a virtual image located 6.0 cm in front of it. For the second converging lens to produce a real image, its object must be located outside of its secondary focal point, which is 8.0 cm in front of it. Since the image from the first lens will be the object for the second lens, the second lens must be placed at a minimum distance of 2.0 cm behind the first lens in order for the second lens to produce a final real image.
  
• r = 16/20:
  Nearly correct, but includes minor math errors. May have not sufficiently explained the conditions for the second lens to create a real image in terms of its object and focal length positions.
  
• t = 12/20:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least determined the location of the image produced by the first lens, and some attempt at constraining the location of the second lens.
  
• v = 8/20:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner.
  
• 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:
Section 70856
p: 7 students
r: 1 student
t: 3 students
v: 3 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 7673):

Another sample "p" response (from student 0097):

Astronomy in-class activity: OBAFGKM poetry slam (NCC)

Astronomy 210, Fall Semester 2010
Cuesta College, San Luis Obispo, CA
(North County Campus)

Astronomy 210 In-class activity 14: OBAFGKM Poetry Slam

Students were instructed to use at least OBAFGKM, and/or part or all of the additional OBAFGKMRNSC or OBAFGKMLT extensions to individually write an original, coherent and an appropriate (nothing worse than "PG-13" rated!) mnemonic, and to give a rousing reading of their OBAFGKM mnemonic poem for the class.

Oh Boy Angie Fights Greatly Killing Monsters
--I. A.

Our Baby's A Greak! God Kill Me!
--C. B.


Odysseus Begged Athena For Guidance in Killing Many Lusty Trojans
--B. B.

Oh Boy, Another Fat Gator Kills Man Right Near Sand Creek
--T. B.

Once Bound, Assisted Free, Gallant Knight, My Rescuer, Now Swooning Comes
--K. C.

Only Bad Asses Fight Giant Killer Monsters
--S. C.

On Bears Angry Fear Goes Kilometers or Miles
--C. C.

Oh Boy Ask For Good Karma this Morning
--K. C.

Our Brilliant Astronomers Failed Gauging Kelvin, Man
--R. C.

Oozing Boots Are Freakin' Great for Kicking Monkeys
--M. G.

Odin's Breakfast Always Features German Kick-@$$ Muffins
--J. G.

Obama Beat A Fierce Giant Killer Midget
--S. H.

Obey Behemoth Ants For Great Killing Madness
--D. J.

Our Brother Aragorn Found Goblins Killing Men
--A. L.

Orion Begged And Fled Gorilla Killing Monkeys
--P. M.

Only Bad Apricots Ferment, Giving Kind Mellowness
--L. M.

Only Batman Avenges For Good, Killing Many Newborn Seals
--K. M.

Oblivious Boisterous Apes Forever Gone Krazy Mad
--T. P.

Ostriches Battle A Fierce Gorilla KarateMaster
--H. P.

Our Baseball-Appropriate Fans Get Killer Monkeys--So Rally, Not Clap
--A. R.

Odd Black Ants Fight Giants Kicking Men
--R. R.

Odd Beavers Acting Fancy Get Kicked Madly
--B. R.

Oh Beauty, Always Fading, Growing Keenly Morose
--K. R.

Oh Bobby Ate Flying Gorillas' Killer Mangoes
--B. S.

Oh Boy, All Flower Girls Kiss Monsters!
--K. S.

Odd Brazilian Attacks Fatal Giant Killing Machine
--D. S.

One Brutal Astronomer Fought Gnarly Karate Masters
--D. S.

On Board A Friggin' Giant Kayak, Man
--T. S.

Obnoxious Baboons Ate Fred's Giant Koala Meat
--C. S.

Ostrich Babies Always Feel Good Kissing Monkeys
--J. V.

Oh Bother, Another Fox Gone Kinda Maniac
--S. W.

On Big African Field, Gators Kill Monkeys
--J. W.


Orange Birds All Flying Go Killing Mammals
--M. W.

Only Beer And Fishing Give Killer Moods
--N. Z.


Previous post:

• Astronomy in-class activity: OBAFGKM poetry slam instructions.

Astronomy in-class activity: OBAFGKM poetry slam (SLO)

Astronomy 210, Fall Semester 2010
Cuesta College, San Luis Obispo, CA
(San Luis Obispo Campus)

Astronomy 210 In-class activity 14: OBAFGKM Poetry Slam

Students were instructed to use at least OBAFGKM, and/or part or all of the additional OBAFGKMRNSC or OBAFGKMLT extensions to individually write an original, coherent and an appropriate (nothing worse than "PG-13" rated!) mnemonic, and to give a rousing reading of their OBAFGKM mnemonic poem for the class.

Ooo Baby A Fat Girl Kissed Me
--I. A.

Oh Bummer A Frog Got Killed Monday
--C. B.

Ooompa-Loompas Broke A Fat Guys Knees Murderously
--M. B.

Only Buy Another Foul Generic K-Mart Meat
Oppenheimer's Bomb Apparently Forged God's Killing Machine
--T. B.

Only Bright Astronomers Find Great Knowledge Meaningful
Only Bad Ass Friends Get Kinky Mistresses
--P. B.

Orange Baboons Always Flick Goobers Kindly My way
--J. C.


Orion's Belt Already Fell, Grab Khakis Man
--C. C.

Overly Bouncy Aliens Frequently Guarantee Kissable Martians
--B. D.

Oranges, Bananas and Figs Give Kyle Major Liquid Troubles
--A. F.

Oh Bummer, A Fat Guy Kicked Me
--J. F.

Oakland Breeds Awareness For Guns, Killing, Mugging; Love This town
--C. G.

Mickey Killed Goofy For A Body Organ
--J. H.


Officer Bob Almost Found George's Killer Machete
--M. H.

Our Belugas Are Friendly Giants, Keep in Mind
--L. H.

Oh, Boyfriends Always Forget Good Kissing Memories
--H. H.

Other Brothers Are From Graciously Kind Mothers Really Nursing Smelly Covers
--N. H.

Obviously Big Ants Feeding Generously Kills Mood
--E. H.

Oranges Believe Apples Feel Gorgeous Knowing Magic
--M. J.

Only Big American Farmers Go Killing Monsters
--N. K.


Oh Boy, Another Fun Game of Kicking Midget Lemurs Tomorrow
--M. L.

Obama Bears Arms For Greatly Killing Mutant Rhinos Near South Carolina
--K. M.

Only Bang's Astral Finish Grabs/Kicks Monstrous, Real Nail. So Cool!
--B. M.

Or Before Actually Failing Geometry go Kick your Maestro
--L. M.

Only Big And Furious Giants Kill Men
--J. R. P.

Our Brilliant Astronomers Find Giant Killer Mr. Len...Terrible
--J. K. P.


Oh Bears Are Freakin' Great Killer Musicians
--J. R.

Only Bad Asses Fight Giant Killing Monsters
--L. S.

Oh Boy, Adulthood Feels Great Knowing My Romantic Ninja Steals Crap
--J. S.

Oranges Bite Apples, Fight Grapes, Kick Mangos, Run, No Student Comments
--J. T.

Oddly Bananas Are From Green Killing Machines
--N. T.

Obese Babysitters Are Firmly Groping Kindly Midgets
--D. U.


Oh Boy! Are Freaks Going Kind, Madly Renting New Space Cars
--B. W.

Oh Be A Friend Grading Katherine's Midterm
--K. W.

Odd Bats And Flaming Guano Killed Me
--E. W.

Oh Boy, Another Funny Glee Keeps Me Loving Television
--B. Z.

Previous post:

• Astronomy in-class activity: OBAFGKM poetry slam instructions.

Physics midterm question: attraction via charge induction

Physics 205B Midterm 1, fall semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 16.14

A Physics 205B student holds a charged plastic rod near a neutral conducting rod, hanging from a non-conducting string attached to its center. Discuss why the neutral conducting rod will always be attracted by the charged plastic rod, regardless of whether the charged plastic rod is positive or negative. Explain your reasoning by drawing diagrams using the properties of charges and induction.

Solution and grading rubric:

• p:
  Correct. Electrons are mobile in the conductor (while protons in atomic nuclei sites are fixed). Bringing a positively/negatively charged plastic rod nearby will attract/repel the electrons in the conductor, which will cause the end of the conductor to have a negative/positive charge, which is a stronger attractive force (due to being closer) than the positive/negative charge on the far side of the condcutor, which will have a weaker repulsion force (due to being farther). Thus the net force on the conductor will be attractive.
  
• r:
  As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes. One argument missing or switched. Has protons mobile in the conductor, or did not explicitly consider the second case where the plastic rod has the opposite charge.
  
• t:
  Nearly correct, but argument has conceptual errors, or is incomplete. Both omissions in (r).
  
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• x:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y:
  Irrelevant discussion/effectively blank.
  
• z:
  Blank.
  

Grading distribution:
Section 70856
Exam code: midterm01voL7
p: 7 students
r: 3 students
t: 1 student
v: 0 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 9999):

Physics midterm question: dichroic mirror

Physics 205B Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Comprehensive Problem 25.67

[10 points.] A thin transparent film (n = 1.60) is coated onto a glass plate (n = 1.51). If this film is to minimize the transmitted intensity for a given wavelength, which equation should be used: ∆l = mλ, or ∆l = (m + 1/2)*λ (where λ is the wavelength value in the film)? Explain your reasoning using the properties of phase shifts and interference.

Solution and grading rubric:

• p = 10/10:
  Correct. (1) Minimize transmission means strong (constructive interference) reflections. (2) The reflection of light in air off of the film has a 180° phase shift, while the reflection of light in the film off of the glass has no phase shift, thus the reflections are out of phase. (3) Thus for constructive interference delta(l) = (m + 1/2)*lambda should be used (where delta(l) = 2*t, and lambda is the wavelength in the film = lambda_air/n_film, but further work using these is not necessary).
  
• 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. One argument missing or switched.
  
• 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/application of ideas, but credit given for effort rather than merit.
  
• y = 1/10:
  Irrelevant discussion/effectively blank.
  
• z = 0/10:
  Blank.
  

Grading distribution:
Section 70856
p: 7 students
r: 3 students
t: 1 student
v: 0 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 7111):

Astronomy current events question: Saturn's aurorae

Astronomy 210L, Fall Semester 2010
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!)

Astronomy.com editors, "Cassini Captures New Views of Saturn's Aurora," September 24, 2010
http://www.astronomy.com/asy/default.aspx?c=a&id=10269

New detailed images of Saturn's __________ have been recently extracted from data taken by the NASA Cassini spacecraft Visual and Infrared Mapping Spectrometer instrument.
(A) aurorae.
(B) rings.
(C) moons.
(D) lightning.
(E) polar ice caps.

Correct answer: (A)

Student responses
Sections 70178, 70186, 70200
(A) : 53 students
(B) : 10 students
(C) : 5 students
(D) : 0 students
(E) : 1 student

Astronomy current events question: Cassini flybys of Titan

Astronomy 210L, Fall Semester 2010
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!)

Jia-Rui C. Cook, "Cassini Gazes at Veiled Titan," September 23, 2010
http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100923b.html

The NASA Cassini spacecraft will make a series of flybys of Saturn's moon Titan, in order to closely study Titan's:
(A) active volcanoes.
(B) ice crust movement.
(C) gravitational field.
(D) atmosphere.
(E) core convection.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 1 student
(B) : 8 students
(C) : 4 students
(D) : 49 students
(E) : 0 students

Astronomy current events question: Phobos' origin

Astronomy 210L, Fall Semester 2010
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!)

Kelly Beatty, "Phobos: A Chip Off of Mars?," September 21, 2010
http://www.skyandtelescope.com/news/103436939.html

Observations of Phobos' _________ by the European Space Agency Mars Express Orbiter may provide evidence that Mars' moon Phobos was debris blasted off of the surface of Mars.
(A) mineral composition.
(B) crater density.
(C) overall shape.
(D) lava formations.
(E) dry ice in shadowed craters.

Correct answer: (A)

Student responses
Sections 70178, 70186, 70200
(A) : 43 students
(B) : 15 students
(C) : 4 students
(D) : 2 students
(E) : 0 students

Astronomy quiz question: sidereal motion (2)

Astronomy 210 Midterm 1, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

An observer in San Luis Obispo, CA notices that the constellation Sagittarius is just above the southwest horizon at 9:00 PM on October 5. (Ignore the fact that your starwheel does not include daylight saving time.) Exactly 24 hours later, this constellation will be __________ the southwest horizon.
(A) slightly lower above.
(B) at exactly the same position above.
(C) slightly higher above.
(D) (None of the above choices, as it would not be visible anywhere in the sky.)

Correct answer: (A)

Using a starwheel (planisphere), the position of Sagittarius will shift slightly the next day, as seen by aligning 9:00 PM with October 5, and then aligning 9:00 PM with October 6, resulting in this constellation being slightly lower above the southwest horizon at the same time the next evening. This is caused by Earth's revolution around the sun while simultaneously rotating about its own axis. Response (B) would be true if Earth did not revolve around the sun, and only rotated about its own axis.

Section 70160
(A) : 22 students
(B) : 7 students
(C) : 11 students
(D) : 0 students

Success level: 59% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): -0.05

Previous post:

• Astronomy quiz question: sidereal motion
  (Fall Semester, 2010).

Overheard: rainbows and unicorns

Astronomy 210L, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

(Overheard during an introductory astronomy laboratory on spectrometers.)

Student: (Looking through a spectrometer at fluorescent light tube, which has a faint continuous spectrum along with bright emission lines.) "I'm not sure if this working!"

Instructor: "What do you see? Do you see the rainbow?"

Student: "Uh-huh."

Instructor: "What else do you see? Do you see the unicorns?"

Student: "The...what?!?"

Instructor: "Do you see a bunch of colored lines?"

(Beat.)

Student: "I see them."

Instructor: "Those colored lines are the horns of unicorns."

Online reading assignment question: interesting Midterm 1 astronomy topics

Astronomy 210 Reading Assignment 7, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

101008-interestingwordle
http://www.flickr.com/photos/waiferx/5063488303/
Originally uploaded by Waifer X

Wordle.net tag cloud for interesting topics covered in Midterm 1, generated by responses from Astronomy 210 students at Cuesta College, San Luis Obispo, CA (http://www.wordle.net/show/wrdl/2547634/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

hard, stars, moonphases, orbits, telescopes
eclipses
stars, eclipses, Moon
Stefan-Boltzmannlaw, Kirchhoff'slaw, electromagneticradiation
stars, precession, Moon, planets
starwheels, astronomers, moonphases
moonphases, constellations
eclipses, retrograde, electromagneticradiation
moonphases, telescopes, moonset, moonrise
moonphases, astronomers, telescopes
stars, blueshift, cheese
heat, energy, hydrostaticequilibrium
Bears, beets, BattlestarGalactica, moonrise, moonset, Sun, spectra
starmasses, eclipses, spectra
fusion, stars, constellations
Moon, eclipses, starwheels
awesome, majestic, infinite
Wien'slaw, telescopes
Moon, planets, stars
moonphases, telescopes, constellations
Moon, telescopes, zodiac
moonphases, chromosphere, corona
gibbous, corona, P-dog
Wien'slaw, resolvingpower, lightgatheringpower
moonphases, retrograde, telescopes
astronomers, moonphases, starpositions
Moon, eclipses, Sun
moonphases, microscopes, stars
constellations, moonphases, zodiac
eclipses, moonphases
Earth, Sun, Moon
moonphases, planetfinding, electromagneticradiation
astronomers, moonphases, constellations
telescopes, stars, moonphases, constellations
Sun, Moon, rotation
telescopes, twilight, Sun
telescopes, Moon, P-dog
astronomers, telescopes, planets
constellations, electromagneticradiation, moonphases
moonphases, sunrise, sunset, moonrise, moonset
history, electromagneticradiation, retrograde
retrograde, history, electromagneticradiation
moonphases, astronomers
starwheels
moonhases, atoms, electromagneticradiation
astronomers, moonphases, eclipses
Moon, telescopes, stars
eclipses, astronomers, celestialsphere
astronomers, moonphases, telescopes
constellations, telescopes, mooncycles
Wien'slaw, temperature, spectra
zodiac, motions, cycles, telescopes
parallax, sunposition, constellations
sunspots, retrograde, electromagneticradiation, eclipses
mooncycles, electromagneticradiation, eclipses
eclipses, spectra, Aristotle
interesting, hard, confusing
Sun, electromagneticradiation, moonphases
moonphases, retrograde, absolutemagnitude, luminosity
moonphases
moonphases, electromagneticradiation, Sun
fun, woah, interesting
electromagneticradiation, astronomers, Sun
heat, entertaining, absorbing
telescopes, moonphases, eclipses
astounding, amazing, intriguing, cool
eclipses, electromagneticradiation, photosphere

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.

"I think learning about the various telescopes was the most interesting subject, because they can help see unknown objects that the human eye can't see"

"I found the telescopes section to be interesting simply because of the distances we can 'see.' It's interesting to learn how/why we can get information of things so far away."

"I guess it would be learning about moon phases and solar/lunar eclipses because we can use that knowledge everyday when looking at the moon and seeing what phase its in or trying to predict when the next eclipse will be."

"I think the most interesting topic was The Stefan-Boltzman Law. I liked it because I understood it , but also because it's interesting how luminosity depends on the size and temperature of tghe star."

"i liked learning about the earth's precession because it's interesting knowing the zodiac appears to move over time."

"The starwheel because now I can find the constellations"

"Constellations and starwheels--I like the idea of being able to locate stars/constellations at any given time."

"Ch.3 learning about the astronomers/scientists and how they had different ideas based on what time period they were studying the astronomy. It is interesting how different their opinions were simply because they lived in different time periods."

"I think the moon positions was the most interesting to me because now i can show off my skills in front of everyone"

"Moon Phases because it is interesting to observe the moon and know what phase it is in."

"constilations because there cool"

"I like learning about the light spectrum. I thought it was interesting."

"I was very interested by retrograde motion. It was cool to see how it occurs through different orbits and speeds."

"The different types of radiation and how only certain ones can reach the earths service."

"The moon and it's phases has been one of the more interesting subjects to me. I really don't know why except that it seems to be something that we see everyday and affects our lives but I have never known the basic information about it."

"The moon phases is a subject that i was already familiar with, but we went further in depth. I love the night sky, espcailly the beauty of the moon. I practically worship the moon, it's literally a spritual thing for me."

"The moon phases because I apply it every night when looking at the moon."

"The solar and Lunar eclipses. I have wanted to understand what happens during these for many years, but never really researched it, I now know what happens during an eclipse."

"Quantum leaps"

"I think the most interesting subject is the moon phases. I liked learning about the moon phases and how to find out what phase the moon is when it is rising, directly overhead, or setting, because i think you can help tell time without a clock, and its just plain cool."

"Moon Phases. It is interesting to know the Moon's dynamics."

"Moon Phases"

"Moon Phases, these are most interesting to me because it is something that I can observe on a daily basis."

"All of astronomy is interesting, too hard to choose one thing. Space is so alien and foreign, which makes it interesting."

"the moon stuff"

"mine is figuring out which stars are where so you can use them as a map"

"Eclipses, there are multiple kinds and they are very cool to look at."

"Moon phases because I always wanted to know what they were called and learning about them and finding out where the sun is and all that stuff was interesting."

"Personally I enjoyed the work with the constellations and the moon phases just because those are things we see on a nightly basis. Ive always wanted to be able to identify more constellations."

"The sun, and all it's layers. It's interesting to know a little bit more about the sun, besides the fact that it's the large glowing orb in the sky."

"Star shapes/sizes/temps/distances"

"I found the electromagnetic emisions to be very interesting because of all the information you can find out about stars just from looking at that."

"The Astronomers. I find it interesting how each atsronomer learned from the previous one and how they all play an important part in what we learn about astronomy today."

"My most interesting subject covered was the Moon Cycles because i didn't really know the cycles of the moon were. I think it is really cool that i can go out and look up at the moon and be able to tell what phase it is in."

"the sun"

"telescopes-before i had no knowledge of telescopes"

"The moon, I just think its really cool to look at at night"

"Astronomers. because it is interesting to learn about the history of astronomy and how our ideas about space have progressed."

"The radiation subject has interested me most because it explains how we are able to recieve and transmit the different wavelengths."

"I thought the most interesting subject was light pollution.This interested me not what it has to do with telescopes but about where i live. And i'm glad i live at a dark sky location."

"retrograde motion--how we can explain planets moving in the opposite direction"

"retrograde motion--because we discovered why planets seem to go backwards"

"I like studying moon phases. It's interesting because now whenever I look at the moon, I like that I know what phase it is in :)"

"I was interested in the origins of astronomy and learning how they made discoveries through trial and error."

"The different moon phases, because its awesome to know that something is orbiting aroud the earth."

"Eclipses are my most interesting subject covered on the midterm because I get to experience them and explain them to my friends."

"Learning about the telescopes was the most interesting because i had absolutely no previous knowledge on them."

"Eclipses: fairly simple to understand, but a marvel and beauty to observe from Earth.
phases because its weird to think about how the moon orbits the earth and the sun only hits part of it."

"the seasons and why they exist because of the revolution of our planet"

"The most interesting part is learning about the stars. I had no idea there was so much to know."

"Zodiac Signs, because i love to learn about them?"

"the most interesting subject for me is the parallax because its a very complex way of figuring out the distance something is by the position of your finger and its actually relatively simple."

"Phases of the moon. I didn't know that the moon was that easy to predict when it rises or sets or is directly overhead."

"The moon was the most interesting because I enjoy learning about specific objects in space."

"i really like stars because they are my favorite"

"I liked talking about stars. Interesting understanding how different and complex they can be"

"i liked learning about the phases of the moon because i can actually use that knowledge on a regular basis"

"the moon phases are the most interesting because its cool to see when the moon sets and rises"

"Sun, it's cool to lean about all that energy"

"Kepler's Laws I used to compete in figure skating and know exactly the far out-slower and close-faster"

"The astronomers I like a little history"

"The sun; the identifications of the suns layers were unknown to me before I entered the class."

"Using the starwheels, I love camping and I've always wanted to know more about the sky I look at every day."

"Planetary motion is the most interesting to me. Imagining the planets of are solar system as organized wanderes is intriguing."

"I liked the sun. Miso soup is good!"

"moon phases, because im not sure about all of them."