20100531

Online reading assignment question: confusing Midterm 2 astronomy topics

Astronomy 210, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

100504-confusingwordle
http://www.flickr.com/photos/waiferx/4635742337/
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/2082541/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 on this midterm. (Graded for completion.)

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

Student responses
Sections 30674, 30676
H-Rdiagram
size, luminosity, Stefan-Boltzmannlaw
microwaves, darkmatter, bigbang
redshifts, blueshifts, Dopplereffect, universeexpansion
redshifts, universeexpansion
redshifts, dust, debris, spiralarms
laws, theories, asteroids
whathappensinsidestars
Deneb, Polaris, Wienslaw
nucleosynthesis, starformation
supernovae, starclusters, pulsars
bigbang
diskpopulation, MilkyWay, granddesign, parallax
Dopplereffect, luminosity
MilkyWay, mass, whitedwarfs, Olbersquestion
sunspots
huh? what?
hydrogen, fusion, helium
starlifetimes, galaxies, stars
MilkyWay, redshifts, blueshifts
absorptionspectra, emissionspectra, darkmatter
mass, redshifts, universeexpansion
alot
alot
abstract, different, strange
globularcluster, densitywave, hydrostaticequilibrium
apparentmagnitude, MilkyWay, Hubbleslaw
finitespeedoflight, bigbang, redshifts
radioactiveblanket, lithium, neutronstars
Dopplereffect, reflectionnebulae, distances
starlifetimes, galaxies, stars
absorptionspectra, emissionspectra, darkmatter, antimatter, finiteuniverse, wtf
starbirth, stars, starages
infiniteorfinite
starevolution
gas, light, stars
puzzling, hardtograsp, difficult
supernovae, Keplerslaws, stars
novae, typeIasupernovae, typeIIsupernovae
laws, parallax, molecules
technicalwords
structure, starformation, universeexpansion
starcomposition
planetformation, galaxies, universeexpansion
galaxies, stars, planets
none
redshifts, startimeline, nucleosynthesis
planetdistances
gaps, theories, laws
theories, spectra, reionization
bigbang, MilkyWay
cosmicmicrowavebackground, beginning, protostars
cosmicmicrowavebackground
laws, nebulas, telescopes
bigbang, galaxies, Dopplereffect
Dopplereffect, chromosphere, inonization
Dopplereffect, electrons, planetarynebulae
stars, supernovae
theyareconfusing
allofit
MilkyWay, luminosity, Dopplereffect
none
Dopplereffect, planetformation, starages, galaxies
Dopplereffect, lookbacktime, redshifts
everything
perplexed, flummoxed, disconcerted
cosmicmicrowavebackground
starlives, supernovae
nothing
starclusters, electrons, luminosity
blackholes, neutronstars, typeIIsupernovae
Dopplereffect, Wienslaw, starlifetimes
everything
Keplerslaws
redshifts, Weinslaw,
cantremember
blackholes, starclusterages
galaxies, MilkyWay, galaxyformation
darkmatter, antimatter, cosmicmicrowavebackground
blackholes, bigbang, Pluto
mindboggling, puzzling, frustrating
everything, inclassactivities, reading


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.
"lunar and solar eclise dont know what kind of eclipse it is showing""the most confusing subject for me is deciding whether or not a star pattern can exist."

"redshifts the doppler effect and size and luminosity"

"i thought one confusing topic was how they can tell how far away other galaxies really are from earth."

"universal expansion. I just don't get it. the universe is expanding, but where is the center and does the center even exist?"

"ANYTHING ABOUT THE GALAXY BLOWS MY MIND. I think its because its too huge."

"last question on midterm.."

"i reallly cant remember what was on this midterm!"

"wien and stefan-boltzmann laws, just didn't go over them enough."

"Math, because all the formulas are really hard to remember"

"I didn't understand the black hole concepts. i just didn't study enough."

"The big bang makes sense in theory, but it's a difficult concept to comprehend how everything can come from nothing"

"The disk population is still a little confusing to me because I missed the lecture."

"Everything after the first midterm. I felt the information was covered way to quick and I wasn't able to grasp it"

"the concepts aren't confusing, but some of the inferences drawn are."

"Stuff that dealt with chemicals was confusing to me."

"The stuff about the universe forming."

"The most confusing subject for me is determining the ages of star clusters and the death of stars. The age of star clusters is confusing because when looking at a plot of star clusters I tend to get the older stars and the younger stars mixed up. Its also kind of confusing to look at a star cluster graph and to see the plotted star clusters and decipher if they are moving toward or away from the main sequence line. The death of stars can be confusing especially discussing the process of a massive star becoming a black hole."

"when hydrogen and helium fused confused me because i couldn't figure out what the book was talking about."

"it was all equally confusing some parts clicked better than others"

"math because I'm not to good with numbers"

"The absorption and emission spectrum's still really confuse me. First of all, distinguishing which is which, and second, exactly what they mean. I know the definition but I'm having trouble understanding it."

"the idea of an expanding universe is confusing to me because it is ahrd to beleive the universe is still expanding and that there are no edges"

"id have to see the mid term"

"The radial arms in the universe."

"I had a hard time understanding the H-R Diagram at first. There are just so many concepts on the diagram that you need to know and understand. Once I got them though it made sense. It was just a little bit hard for me to grasp at first."

"I was confused most by the Hubble theory because I missed the class where you explained it."

"the finite speed of light, it doesnt make sense"

"I think I missed a class when I was sick and didn't get all the notes, but it would be the radio active blanket or something..."

"doppler shifts, i didn't like the wording, i assumed it meant why the universe is expanding?"

"it was all equally confusing some parts clicked better than others"

"I'm still having trouble understanding the spectrum, mainly absorption and emission, and don't even get me started on anti-matter! I mean seriously! dark matter wasn't enough! haha"

"its all kind of confusing just some stuff more then other stuff."

"Necleosynthesis: the example of the a croded area and a dense; arm universe"

"graphs multiple choice and short answer"

"on how stars become black holes"

"The most confusing part was all the specifics of the big bang and just how anyone is supposed to know them."

"the truth is i have had confusion on most parts of astronomy"

"different types of novas- which is which"

"Still just a little shaky on the differences between the three. The firecracker demonstration helped a little...I know one has a more slow burn vs. explosive burn, but I still get which is which confused."

"n/a"

"The order of a stars life and star clusters"

"The structure and formation of stars confused me the most because there's so much chemistry involved dealing with nuclear fusion and bonding that it was hard to keep it all straight in my head. Chemistry was never a strong subject for me, and I struggled through anything dealing with metals, bonds, or the different types of fusions occuring in stars of different masses."

"i thought the convectio and overall atomic changes within the life of a star was hard to keep up with"

"planet formation and planet death involving helium and hydrogen ratios and interactions. I just couldn't get a good grasp on it."

"galaxies, the way they work"

"english just hard for me to write essays"

"how galaxies are formed. i feel like i missed the qestions about the stars on the spiral arms on the midterm"

"Categorization of suns with letters and numbers, i just didn't get it."

"just remembering terms"

"No Subjects were too confusing"

"Maybe I missed the class or something but the redshifts didnt make sense to me."

"how to tell which planets where the farthest and closet to the earth"

"Star recreation, just had a hard time grasping it al"

"emission spectrum. the definitions of different spectra were confusing as radiation and emission properities seem closely related as heat by-products."

"Some of the theories,i was absent for some"

"the reionizing and background microwave was hard for me to remember"

"I'm not sure of the CMB and what its cause is"

"The milkyway, it was a little confusing to know the spiral arms and how they get created.
the big bang theory, even though it was really interesting, there was so many parts to it that i found it overwhelming
doppler affect, i didnt get it at all."

"In planetary nebulas, it's difficult to keep massive, main-sequence and low-mass stars straight."

"i couldnt remember all of the names for the theories"

"The light specrums, because it's hard to remember what spectrum belongs to what light source."

"the house party because you never really tell us when to go over."

"I think the milky way question was the most confusing because I can never remember what the theory was that the milky way became thinner and flatter..."

"non"

"star age in galaxies, just never solidified in my mind."

"I understand most of the stuff we go over but, i don't think i have an open enough mind to accept a lot of the theories."

"During every example there where things I understood and didn't. Too many to list."

"Dobbler and Hubble because I get them mixed up."

"Cosmic microwave background because I don't even remember learning about it."

"supernovas and type 2 supernovas. i can never remember which is which"

"The table depicting the luminosity, size, and temperature (Stefan-Boltzmann Law). It took more time for me to wrap my brain around."

"Supernova Explosion, I just never quite understood how they formed or how they came about"

"Black holes, because they're still very hard to understand."

"the doppler effect.. i didnt study for this i guess!"

"Mostly everything. I always feel like i know these things and feel as if i did really good on a test, but the results are really bad. so idk if i grasp the concept of things just for a moment and then forget or something."

"describing weather two planets were simlar in size, luminosity, etc."

"One of the essay questions confused me, the one about vera and polaris and if it was possible if they were the same size. I was stuck on it for so long!"

"I just got confused on the 1st short answer question because i went over the in class activity but i didn't see that the tem/lum were higher on the same star in order for them to be equal. Oops ="

"the star clusters and how you determine whether they are younger and older"

"galaxies because i missed that week"

"darkmatter. I still don't understand how all the stars in the galaxy move at the same speed. I thought they moved at different speeds which showed us an idea of the size of our milky way galaxy"

"big bang i do not believe in these things"

"The most confusing subject for me was figuring out star distances. It was confusing to me because I actually needed to see the problem on paper and not just figure it out in my head. After I was shown a way to do this on paper, I understood and grasped the concept."

"ALL OF THIS UNIT!"

20100530

Online reading assignment question: interesting Midterm 2 astronomy topics

Astronomy 210, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

100504-interestingwordle
http://www.flickr.com/photos/waiferx/4636348546/
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/2082525/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 on this midterm. (Graded for completion.)

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

Student responses
Sections 30674, 30676
density, reddwarfs, spiral
redshifts, Dopplereffect, size, luminosity
galaxies, blackholes, nebulae
binarystars, supernovae, universeexpansion
stars, starclusters, luminosity
moon, stars, gas
stars, bigbang
H-Rdiagram, MilkyWay, universeexpansion
Wienslaw, H-Rdiagram, stars, nebulae, universeexpansion
stars
starlifetimes, stardeath, temperature
MilkyWay, stardeath, absolutemagnitude
Stefan-Boltzmannlaw, Hubbleslaw, finitespeedoflight
deathofstars
blackholes, typeIIsupernovae, typeIasupernovae
bigbang, starformation, MilkyWay
stars, temperature
galaxies, diskstars, halostars
galaxies, blackholes, MilkyWay
starformation, planetarynebulae, typeIIsupernovae
stars, nebulae, galaxies
notmuch
MilkyWay, luminosity
nebulae, H-Rdiagram, Hubbleslaw
MilkyWay, sunspots, emissionspectra
novae, H-Rdiagram, light
stars, darkmatter, age
supernovae, luminosity, MilkyWay
galaxies, MilkyWay, halostars
bigbang, universeexpansion, starformation
stars, starformation, starlifetimes
livefastdieyoung
explosion, universeexpansion
galaxies, stars, Dopplereffect
difficult, vast, mindopening
bigbang, stars, supernovae
stars, novae, supernovae
starlifecycles, blackholes, neutronstars, bigbang
stars, starformation, hypotheses
Blackholes, supernovae
stars, blackholes, galaxies
blackholes, spaghettification, pulsars
planetsize, luminosity, temperature
dwarfstars, redshifts, planets
bigbang, stars, telescopes
blackholes, redshifts, bigbang
stardeath, bigbang, finitespeedoflight
supergiants, planets, blackholes
Hubbleslaw, Kirchoffslaws, H-Rdiagram
blackholes, bigbang, MilkyWay
bigbang, starmasses
universe, redshifts, brightness
blackholes, Hubbleslaw, cosmicmicrowavebackground
bigbang
laughable, easy, yes
redshifts, expansion, H-Rdiagram
starformation, planetformation
spectra, starlifetimes, bigbang
nebulae, supernovae, whitedwarfs
luminosity, stars, planetaryformation
universeexpansion
blackholes, awesome
stars, redshifts
stars, time, light
gravity, darkmatter, planetformation, blackholes
Dopplereffect, bigbang, starclusters
stars, galaxies, blackholes
thoughtprovoking, fascinating, wondrous
supernovae, Dopplereffect, supergiants
MilkyWay, blackholes
planetarynebulae, supernovae, cosmicmicrowavebackground
blackholes, starclusters, Earth
chromosphere, photosphere, corona
luminosity, MilkyWay, Wienslaw
Idontremember
starmasses
MilkyWay, starclusters, cosmicmicrowavebackground
universeexpansion
stars, lifeanddeath, bigbang
light, starlifetimes, bigbang
stars, formation, galaxies
whitedwarfs, reddwarfs, mainsequence, stars
H-Rdiagram, starsizes, luminosity, temperature, fusion
Ijusthardahardtimewiththisunitoverall


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.
"the subject talking about luminosity of different starts and the further back you look the further back in time"

"doppler effect because it applies to stuff in everyday life"

"i thought it was pretty interesting how the galaxies formed."

"binary stars. I just think its cool that 2 stars could borrow energy from eachother. and then eventually become a supernova."

"i really like the apparent and absolute magnitude. I think its cool to try and predict the size and brightness of planets which aren't the same distance away from earth."

"probably all the different types of stars"

"i cant remember what was on the midterm.."

"Universe expansion really interested me, I liked learning all of the theories and explanations. I had never learned about any of this before."

"It was intercultural communication because it covered A lot of what goes on in America, like segregation, hate, racism. Etc"

"the formation of the solar system the theory of the big bang was very interesting because it is the beginning."

"The novas and supernovas because they are such unbelievably violent reactions."

"I like the HR diagram because it makes sense to me."

"The first week when we talked about the star wheels that was the only subject that I really understood out of the whole semester"

"The expansion of the universe as shown by Hubble's law is such a foreign conscept to me being as the space around me never expands."

"Supernovas because they were cool."

"supernovas, because things exploding is cool."

"The most interesting subject was discussing the Big Bang and how everything in the Universe is made up of extra stuff, because it survive annihilation."

"massive main sequence stars fuse hydrogen and helium"

"i like the whole relevance of the universe and the way its moving and that whole subject i find it interesting"

"astronomy because your learning about new unknown areas"

"I really liked the explanation of coming and going of stars on the main-sequence. The 'House Party' example! It was really easy to understand and interesting too."

"I was most interested in galaxies because i did not know much about them and was interested to learn how big they are."

"the beginning of the class cause that seemed more astronomy than science.
The light spectrum. This is very useful material to use in everyday life."

"I think it was interesting learning about size/distance/luminosity/mass of stars. It is crazy that there are ways that we can figure all of these things about stars even though they are light years away from us. It proves how much since has advanced over the years."

"Im most interested in the Milky way because It is what I felt I learned least about as a child."

"the big bang, cause i think its a hoax, there are too many flaws in the theory"

"I really like determining the age of stars of the luminosity, temp, size. "

"It's fun and uses reasoning and just adds a little spice to straight memorization and regurgitation on exams."

"the milky way: because i knew it was big, but not as unfathomable big as it is"

"i like the whole relevance of the universe and the way its moving and that whole subject i find it interesting"

"The Big Bang has always been of interest to me, it was nice to learn some that I didn't know already."

"i'm not sure which subject is most interesting. its all kinda interesting."

"How massive stars use up hydrogen faster and live shorter lives as appose to low mass stars . yet the sun has been burning since it has been discovered, many many years before the homosapien started studying it and its still around."

"the box thing we did to see the size lum or temp. it was a simple tool that we can learn so much from"

"it was interesting on how big/small or hot/cold stars could get"

"The section on the timespan of the big bang I felt was most interesting. "

"Just the scope of what was covered is one of the main reasons I took this class."

"expansion of the universe, it's interesting how th universe is expanding, will the expansion stop and the niversecollapse on itself?"

"time travel, because if we can get into time. who knows the endless possibilities"

"I liked learning about the big bang and the expanding universe and how we discovered the evidence behind it."

"Learning about binary systems, and how/why novas and supernovas occur were the most interesting topics to me- mainly because i had no prior knowledge about them."

"I like learning about the stars and their temp compared to mass"

"The most interesting subject for me was the death of stars. I enjoyed learning about how different sized stars have completely different deaths, and what kind of cataclysmic result comes from the death of these stars. The concept of black holes also largely fascinates me, and it's something I would want to look more into."

"i think the black holes and nuetron stars where most interesting since they are the most dense and powerful known bodies in the univers"

"nebula's because we can really see them in the sky and it is more concrete than other topics."

"the red and white dwarfs, the difference between them"

"i find that business"

"black holes, because i dont completely understand them"

"Finite speed of light, because looking into the past is fascinating."

"the planets because i would like to think we could live on some of them one day"

"Hubble law, the development of the universe is very interesting, we all want to know how we got here and whats going to happen."

"the big bang was very interesting because I always wondered how astronomers even theorized that there was one and now I know!"

"to see how everything was created and to see how scientist comes up with theory's on how it happen"

"The idea that the universe has an end we can see is just mind blowing to me!"

"the big bang theory. its a representation of the combined efforts of thousands of years of thought and ambition that motivates and perptuates discveries to come."

"the HR diagram,milky way and thats about it"

"star life was pretty cool. having to do with explosions."

"expansion of the universe is cool because it leads back to the big bang."

"distance between planets"

"I really enjoyed learning about the stars and being able to compare them using the H-R diagram because stars are my favorite thing in the sky
novas, because they go boom!"

"The H-R diagram was easy to understand and made sense and I actually had fun figuring it out."

"i liked how we proved that there was no big bang theory"

"All of astronamy interests me!"

"the milky way because it reminds me of the candy."

"I liked the essay question about the stars on the HR diagram example. It was fun to write about why this example was impossible."

"the finite speed of light, because it is interesting how we are viewing pockets of time when we look in to the sky"

"gravity/dark matter, the origins of gravity are interesting to me."

"I was really interested to understand more about the big bang theory and how the general scientist believes the univers began...i believe in the fact of creation but its still interesting to see other view points"

"Galaxies, i think it's fascinating not knowing what is out there."

"Star clusters because they were easy to understand."

"Supergiant stars because it's just amazing to imagine a star that's of such epic proportions."

"black holes because we dont know exactly what it is"

"The expansion of the universe and how it is expanding. The idea that space itself is expanding is very intriguing to me."

"Black Holes, for whatever reason they have always interested me and now I have finally learned about them"

"types of super nova explosions."

"i liked the essay question about the the size and luminosity of two stars! you didnt ask to draw a picture but i did anyways.. it makes more sense to me when i draw it!"

"i dont remember"

"the life span of stars"

"i really enjoyed learning about the cosmic microwave background because you did a very good visual with the movie showing examples the dancing/moshing"

"The expanding universe because it's the galaxies but the spaces in between that are expanding."

"the big bang because i had never understood the theory"

"the 'big bang' because i've heard the phrase but didn't know what that theory was and have always been courious on how the universe was created"

"Galaxies. It is so amazing to ponder at how much mass is out there!"

"the stephan law thing and about how a star can be smaller and brighter becasue the larger star has a faster fusion rate"

"The most interesting subject to me was discussing the H-R Diagram on how stars came, left, or stayed on the main sequence line. I also enjoyed learning what these stars became after their fusion was finished. I liked how this concept was related to a house party."

"Once again, I just hard a hard time with this unit."

20100529

Cuesta College North County campus star party

100415-1150373
http://www.flickr.com/photos/waiferx/4620396177/
Originally uploaded by Waifer X

Waxing crescent moon, April 15, 2010, photographed with a handheld Panasonic Lumix DMC-LZ8 camera through a Orion 10" reflector at Cuesta College North County campus, Paso Robles, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.


100415-1150381
http://www.flickr.com/photos/waiferx/4621009196/
Originally uploaded by Waifer X

Venus and waxing crescent moon, April 15, 2010, photographed with a Panasonic Lumix DMC-LZ8 camera set on long-exposure mode at Cuesta College North County campus, Paso Robles, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.

Sights seen:
Waxing crescent moon
Venus
Saturn

20100528

Online reading assignment question: opinions on Pluto

Astronomy 210 Reading Assignments 14-16, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com). Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect.

(The following question was asked subsequent to, and then again following the lecture discussing the International Astronomical Union classification scheme of moons/satellites, solar system debris, dwarf planets, and planets, which included a group in-class activity.)

I believe Pluto should be a planet. (Graded for completion.)
(SD) Strongly disagree.
(D) Disagree.
(N) Neutral.
(A) Agree.
(SA) Strongly agree.

Student responses (pre-instruction)
Sections 30674, 30676
(SD) : 6 students
(D) : 11 students
(N) : 28 students
(A) : 23 students
(SA) : 25 students

Student responses (post-instruction)
Sections 30674, 30676
(SD) : 13 students
(D) : 22 students
(N) : 25 students
(A) : 17 students
(SA) : 10 students

Of the 94 students who had answered the pre-instruction question, and the 87 students who had answered the post-instruction question, 70 students had answered both the pre-instruction and post-instruction questions (while 24 students answered only the pre-instruction, and 17 students only answered the post-instruction question).

Of the 70 students who answered both the pre-instruction and post-instruction questions, 32 students had no change in their opinion, while 38 students changed their opinion.

Student responses (pre-and post-instruction responders, no change in opinion, N = 32)
Sections 70158, 70160
(SD) : 3 students
(D) : 3 students
(N) : 13 students
(A) : 9 students
(SA) : 4 students

Student responses (pre-and post-instruction responders, change in opinion, N = 38)
Sections 70158, 70160
(SD) : pre: 2 students; post: 6 students
(D) : pre: 4 students; post: 15 students
(N) : pre: 10 students; post: 7 students
(A) : pre: 11 students; post: 6 students
(SA) : pre: 11 students; post: 4 students

A Student t-test on all 70 students who answered both the pre-and post-instruction questions (32 students with no change in their opinion together with the 38 students that changed their opinion) results in p = 0.0073, and thus there is a statistically significant difference between pre-and post-instruction responses.

For the students who took both and responded differently to the pre-and post-instruction questions, here were the shifts:

(SD) to (A): 1 student
(SD) to (SA): 1 student
(D) to (SD): 3 students
(D) to (A): 1 student
(N) to (SD): 1 student
(N) to (D): 7 students
(N) to (A): 1 student
(N) to (SA): 1 student
(A) to (SD): 1 student
(A) to (D): 3 students
(A) to (N): 5 students
(A) to (SA): 2 students
(SA) to (SD): 1 student
(SA) to (D): 5 students
(SA) to (N): 2 students
(SA) to (A): 3 students

"Negative shifts" in opinion (e.g., towards disagreement): 31 students
"Positive shifts" in opinion (e.g., towards agreement): 7 students
(Compare with the 32 students with no shifts in opinion.)

It appears that there is a greater shift towards negative opinions towards Pluto being a planet in this small population sample, as the students that changed their mind were apparently affected by a single lecture on the IAU classification scheme, and on the historical (re)definitions of planets and changing numbers of planets.

Students were given the opportunity to explain their pre-instruction opinion, responses are listed below verbatim.

Briefly explain your answer to the previous question (whether Pluto should be a planet). (Graded for completion.)
"dont have an answer"

"just cause"

"they can't just take his title away thats just mean"

"if pluto not long ago was a planet, then why remove it from the solar system as a planet"

"we have enough"

"well its been classified as a planet for like forever soo i think they should just keep it that way"

"its more just a chunk of ice"

"because pluto and i go way back."

"Now we have to come up with new things to tell our children so they can remember the plants!"

"we can't just disregard her after we already named her a planet. that's like giving someone a present and then taking it back. rude."

"i really liked pluto."

"Im not sure"

"I don't really care about classifications like 'planets.' It all goes around the sun."

"pluto has a very thin atmosphere."

"I dont know...I just LOVE it!!"

"because it is"

"because goofy IS a dog who owns a dog named pluto and he's treated unjustly, then all of the sudden this planet is treated unjustly because of his name and is no long a planet. We need to leave all plutos alone."

"Becuase pluto is wack!...Pluto cannot hang with the rest of the planets."

"It's been considered a planet for a very long time, and now all of a sudden scientists want to change it."

"its located in our milky way galaxy"

"because its big!"

"A Dwarf Human is a Human, so a Dwarf Planet is a Planet."

"Because at on point on it's journey around the sun it is closer to the sum than Neptune."

"because it always has been"

"it doesn't really fit in with the rest of the outer planets"

"Because the whole debate for Pluto's 'planet' status being revoked is based on a trivial definition of what a planet is."

"I don't know enough about it!"

"Ever since i have gone to school it has been called a planet so i don't understand why things have changed"

"I haven't gotten that far in my reading yet."

"not a planet due to it's large orbital tilt and eccentricity."

"Beacuase it was always was a planet, why change now?"

"I dont really have an opinion."

"It's part of the Kiper Belt outside of our solar system, but it will occasionally enter the solar system."

"because i like mickeys dog"

"I like the idea of Pluto being a planet, because it's been one every since I can remember. Not having it as a planet is like telling me that a little piece of my universe is suddenly false..."

"But I guess if 'They' deem it not a planet, then we have to deal..."

"I feel bad, its left out."

"I would have to concur with the International Astronomical Union. A planet is defined as a celestial body that orbits around the sun, has sufficient mass to maintain hydrostatic equilibrium and has cleared the area around its orbit. Due to the fact that Pluto's orbit is irregular and Pluto's gravity is just large enough to have pulled it into a spherical shape, but not enough to clear out its orbit."

"I don't know enough to call it a planet or not."

"pluto is the best says Grandma"

"its in our galaxy"

"it is too small to maintain a orbit correctly"

"I don't care."

"Technically pluto should not be a a planet but growing up it was definitly taught to be a planet, and i think 'once a planet always a planet'"

"Because it was a planet for so long!"

"I think it has been proven that Pluto is not a planet and is rather somehting else,it is not an opinion or belief."

"its just a moon from other planets"

"Pluto should do what it wants its a big boy now."

"I only agree because it was taught to us You can't unteach what was engraved in a childs mind. It's just cruel."

"I dont know enough about it to know if it qualifies as a planet. I learned about it as a planet growing up though so I think it should stay a planet."

"Planet!? Pluto is Mickey's dog!!!!"

"I dont really care"

"its an ice cube not a planet"

"it just should"

"Because 'My Very Elegant Mother Just Served Us Nine....' just doesn't make sense"

"i was always taught that pluto was a planet, but now that it isn't considered a planet anymore, i don't really care."

"Because it was a planet earlier"

"I don't disagree or agree because Eris exists beyond Pluto, therefore the definition of a planet had to be questioned. This was the conclusion astronomers reached."

"I agree because when I was little I always associated Pluto with the planets"

"because you can't toy with my childhood like that"

"I'm not certified or educated enough to make a statement in deciding if Pluto is a planet or not.
because plutos my dawg just like p-dawg"

"i think its unfair that it was and now its not a planet but i kinda of dont mind it either way.."

"Because it's pluto! Duh!"

"im not sure if it should be a planet or not."

"since its neither Jovian or terrestrial yet it has 3 moons and is so cold and far. it mAKEs this planet very unique to our solor system, just because we dont understand its clause doesnt mean its not around for a purpose."

"it's cool like that."

"I am intersted in learning more about it"

"its close to the other planets in our solar system"

"how could it not be?"

"whether pluto is considered a planet or not should not really be that important."

"it was a 'planet' for years, why not eep it that way. the astrological signs are all off by a month but they didnt change that up for the public"

"All im saying is give the guy a little break. i mean he is a planet. then hes not. then he is. now hes not. hes been though a lot and needs to know that he is indeed a planet. telling him may hurt his feelings. plus you know that song that you learned when learning the planets. now thats all screwed up. SAVE PLUTO!"

"Just because it's nostalgic to what we've been taught in elementary school does not make it scientifically accurate. There are also similar Kuiper belt objects that need to be included as planets if we accept Pluto."

"Because I've grown up thinking it's been a planet and now they just change their minds?!! Just because it's a "dwarf plantet" It throws me off ! Why! Now students will have to be more creative when learning the planets and how their very excellent mother didn't bring them pizza after all!"

"It should still be considered part of the Kuiper belt."

"because i was taught when i was little that it was a planet."

"science says that pluto is not massive enough to be considered a planet but instead a star"

"I feel bad for it"

"Pluto should be a planet because it orbits the sun, and has 3 known moons orbiting around it as well. It doesn't fall into our solar system like meteors or comets do, with the only exception being its switch with Neptune every once in a while due to its irregular orbit. Therefore, it cannot be an object in the Kuiper Belt, and should be classified as a planet. This whole "8 planet solar system" thing is stupid."

"Pluto is a body that revolves around the sun. that means its mass is big enough to be a planet. scientists are full of crap"

"doesn't matter to me, just seems confusing that it changed."

"I don't really know if pluto should be a planet or not..."

"i don't really know what pluto is made of/how it was made and i don't really care whether it's a planet or not"

"because it is generally like all other planets"

"because i said so."

"cuz its gangster"

"Its okay, pluto. I'm not a planet either"

"everyone hsa feelings for pluto!"

"It doesn't fit all of the requirements"

"Because it needs respect!"

"why not?"

"As much as I would like Pluto to be a planet, it is not. It has a different orbit than the rest of the planets around the sun. Plus, there have been other objects, like Pluto, that also ordit the sun in this fashion and are not called planets. Why should Pluto be treated any differently?"

"I am not into astronomy enough to answer with an opinion."

"because there are other same size planet like masses orbiting in the same area."


Students were later given the opportunity to explain their post-instruction opinion, responses are listed below verbatim.

Briefly explain your answer to the previous question (whether Pluto should be a planet). (Graded for completion.)
"because of the rules of to be a planet pluto doesnt meet the last one"

"it was"

"The current classification is suitable."

"It doesnt meet the current classifications of a planet."

"It does not meet the requirements to be one. ( sorry pluto)"

"Pluto is very Icy and it does not dominate its orbits"

"just cause i love it...who cares if it doesnt dominate its orbit"

"Because it was once considered a planet.....it's not cool to now change our minds and say it isn't one."

"After knowing the guidelines to be a planet according to the IAU rules, Pluto does not fit the requirements."

"i think it should cuz it pretty much dominates its orbit"

"Pluto is not a planet because it does not meet all of criteria for it to be a planet. In the case of Pluto, it does not dominate it's orbit, so it should not be a planet."

"if it was a plant before then it should still be a planet now. what if someone told you that you can no longer be human"

"I think the IAU's classification is good enough. If it's classified as a planet, then I'd be happy. But it seems that if it doesn't dominate its orbit, it's not spiffy enough to be a planet. I'm satissfied with it being a Dwarf Planet for the moment."

"i agree with the fact that pluto doesn't qualify"

"I really do not care. It seems irrelevant to my life, UNLESS... it turns into a death planet like in that episode of Invader Zim :o"

"technically its still a planet...but a dwarf planet LoL"

"The only reason is because it has always been a planet and things would be easier if it where."

"What good would it do if Pluto is a planet?"

"It doesn't fit the qualifications, but if the standards change, then so should Pluto's status."

"Because it was a planet earlier"

"The IAU's classification suits me."

"It has always been a planet since I was a kid so i do not see why the change it now."

"I don't think it meets the requirements but it has a cool name so I'm neutral."

"because there are a bunch of other "planets" like pluto, so if pluto was going to be a planet then the rest of them would have to be planets as well. not okay with me!"

"It's not important"

"it is in our solar system"

"Because it doesn't dominate its orbit."

"Because if it isnt big enough to dominates its orbit if it was switched with another from the belt, it would not be classified as a planet."

"If pluto was a planet, then we would have like, 8 more planets, and I really don't want to memorize more planets..."

"Pluto doesn't clear it's orbit anymore"

"Um. I dont really care."

"Pluto should not be a planet because it does not dominate its orbit as in the IAU rules."

"I do not have enough of an interest in Astronomy to support my opinion."

"it does not hold the capabilities to serve as a planet."

"why not man"

"you can't just strip little pluto of his planetary title. its rude."

"it's weird that it was considered a planet and now it's not. they should just keep it in there."

"It was considered a planet and then it wasn't. I think it should be one because everyone thinks it is."

"then too many objects in the night sky would have to be"

"It doesn't fit the internationally accepted rules for a planet"

"because there are ton of other planets and objects in the kuiper belt... thats unfair for the other objects in the belt."

"I really like Pluto."

"Because there are many more even larger dwarf planets floating around out there, and we dont want tooo many planets"

"Pluto should not be a planet because it does not fit the profile of a planet."

"Since the planet pluto is within our solar system the "milky way" then it should be considered a planet"

"A Dwarf Planet is still a planet much like a Dwarf Human is still a Human!"

"Because pluto still dominates it's orbit around the sun."

"because it was for so long and they just took it away"

"It doesn't have all the qualities that make up a planet."

"It does not dominate it's orbit."

"Because it has always been in every other science class"

"Because it is so dang confusing when you keep changing it. Poor Pluto must be having an identity crisis!"

"Dont really care either way"

"I think the three rules for planets are good."

"Because it does not meet the requirements of the IAU. It does not meet the specific requirement of dominating its own orbit."

"Dont really know enough about it."

"because i grew up with that!"

"Its in our solar system so it should be a planet"

"Based off the new classification system it should not be a planet."

"We'd have to name too many other dwarf planets to be planets if pluto was still considered a planet."

"Pluto ahs been proven to not be a planet"

"I dont think so since its a moon from Uranus"

"There is a dog named after it so why not keep it a planet?"

"I dont really care."

"it feels sad its left out"

"it is all gas"

"My very eager mother just served us nine..... PIZZAS!"

"now after learning the qualifications for a planet i am ok with pluto not being one."

"Pluto does not fit into the 3rd category of be qualified to be considered a planet. This is not having dominance over it's own orbit."

"Pluto should not be a planet because if it were considered a planet then there would be over 100 planets in our solar system."

"i dunno if Pluto should really be a planet."

"because it does not answer yes to all the questions"

"just because its a different color or temp doesnt mean it shouldnt be a planet"

"it was a 'planet' for such a long time in everyone's eyes. might as well keep it a planet"

"No domination of orbit"

"Pluto doesn't dominate it's orbit!"

"was a planet for most of my life, why change?"

"Used to for so long it being a planet, so why now does it have to change"

"I'm currently neutral on the subject of Pluto being a planet or not. I grew up learning that Pluto was a planet, and it always held an air of mystery about itself because it was the planet furthest from the sun, which had a different orbit than the rest of planets, and I was always fascinated by Pluto and Neptune switching places in our solar system due to Pluto's odd orbit around the sun. However, Pluto is neither terrestrial or jovian, and other Kuiper Belt objects are similar to its composition. So yes, I will always consider Pluto as a planet, but I also understand why it isn't."

"Plutos g"

"It doesn't matter to me"

"Doesnt dominate orbit"

"call pluto an astroid. it starts acting like one!"

"It would just be so sad to get rid of it as a planet after I grew up believing it was a planet."

"because i like pluto"

"well im not truely sure"

"Its hard to change what i've been taught for so long"

"I thought it was a dog"

"its large enough and is still trapped in the suns gravitational pull causing it to have an orbit"
References:
  • Brother Guy Consolmagno, SJ, "What Happened to Pluto?," Astronomy Education Review, vol. 45, no. x, p. 14 (2007).
    (http://dx.doi.org/10.1119/1.2409503)
    "...So in the ultimate sense, what happened to Pluto? ...As a planet, Pluto had always been something of an ugly duckling. But as a newly defined 'dwarf'--a fascinating and important category of solar system objects that until recently we never even knew existed--it's a beautiful swan."

  • Andrew Fraknoi, "Teaching What a Planet Is: A Roundtable on the
    Educational Implications of the New Definition of a Planet," Astronomy Education Review, vol. 5, no. 2, p. 226 (2007).
    (http://dx.doi.org/10.3847/AER2006028)
    "Readers of the Astronomy Education Review are often the ones on the front lines of our educational system, teaching students, meeting with planetarium and museum audiences, and responding to media requests for information. Given all the hoopla about the new definition of a planet in our Solar System by the International Astronomical Union (IAU) at its meeting in Prague in August 2006, we thought it might be interesting to gather a cross-section of reactions from noted astronomy educators and then invite our readers to voice their opinions."

  • James L. Hilton, "When Did the Asteroids Become Minor Planets?"
    (http://aa.usno.navy.mil/hilton/AsteroidHistory/minorplanets.html)
    "The recent controversy over whether Pluto should be given a minor planet number and possibly be demoted from the ranks of the major planets has made me wonder about the similar controversy that occurred 150 years ago. This involved whether or not the bodies discovered between Mars and Jupiter should be considered equal to the seven other planets known at that time."

  • David Jewitt & Jane X. Luu, "Pluto, Perception & Planetary Politics" Daedalus, vol. 136, no. 1, p. 132 (2007).
    (http://www.mitpressjournals.org/doi/abs/10.1162/daed.2007.136.1.132?journalCode=daed)
    "...one cannot buy the level of public interest that has been triggered by the planethood debate. The IAU and astronomers everywhere have the potential to use this interest to focus the public toward more fundamental, more scientific issues, such as the origin of the solar system and even the nature and purpose of science... Let's hope that what ultimately comes out of the planethood debate is a better understanding of what science is about, rather than hollow mourning for the Icy Body Formerly Known as a Planet."

  • Michael C. LoPresto, "A First Glimpse of Student Attitudes about Pluto's 'Demotion'," Astronomy Education Review, vol. 5, no. 2, p. 226 (2007).
    (http://dx.doi.org/10.3847/AER2006029)
    "I asked two sections of introductory astronomy students whether they thought that Pluto should still be considered a planet and to write down why. I asked them specifically to vote yes, no, do not know, or do not care.
          "The results were that 26 of 46 students, almost 57%, voted that Pluto should still be considered a planet; only six (about 13%) voted against Pluto, nine (just under 20%), said that they did not know, and five (almost 11%) said that they did not care.
          "The poll was administered a second time, also unannounced, to 42 students after coverage of the Solar System in the course. This time, 27 students, a 64% majority, agreed with the decision. Among these, 17 said that their opinion had changed based on what they learned in class. A total of 10 students, almost 24%, remained against the decision. Two students said that said they still did not know, and three still did not care."

20100527

Astronomy current events question: M81 halo

Astronomy 210L, Spring 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, "A New Take on M81's Halo," May 3, 2010
http://www.skyandtelescope.com/news/92734814.html
Researchers using data from Japan's Subaru telescope have determined that the halo of spiral galaxy M81 __________ than the halo of the Milky Way.
(A) is mainly composed of antimatter.
(B) contains much more dark matter.
(C) is more abundant in heavy elements.
(D) is much smaller.
(E) has a greater redshift.

Correct answer: (B)

Student responses
Section 30682
(A) : 0 students
(B) : 4 students
(C) : 5 students
(D) : 0 students
(E) : 1 student

20100526

Astronomy current events question: galactic bubble RCW 120

Astronomy 210L, Spring 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, "Herschel Reveals the Hidden Side of Star Birth," May 6, 2010
http://www.astronomy.com/asy/default.aspx?c=a&id=9829
The European Space Agency's Herschel infrared space observatory has revealed __________ in the galactic bubble RCW 120.
(A) the formation of a black hole.
(B) a star that may become one of the Milky Way's biggest.
(C) a wormhole candidate.
(D) the source of dark energy.
(E) carbon-based organic compounds.

Correct answer: (B)

Student responses
Section 30682
(A) : 1 student
(B) : 6 students
(C) : 1 student
(D) : 2 students
(E) : 1 student

20100525

Astronomy quiz question: condensation sequence hypothesis

Astronomy 210 Quiz 7, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

According to the condensation sequence hypothesis, why are the inner planets of the solar system composed of metals/rocks, while the outer planets are composed of ices/gases?
(A) The gravitational pull of the sun.
(B) The sun's magnetic fields.
(C) Strong winds generated by the sun.
(D) Heat generated by the sun.

Correct answer: (D)

Heat generated by the sun means that volatiles cannot condense to start forming the cores of the inner terrestrial planets, while further out, where it is cooler, volatiles can condense to start forming the outer jovian planets.

Section 30676
(A) : 10 students
(B) : 16 students
(C) : 3 students
(D) : 38 students

"Success level": 58% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.55

20100524

Astronomy quiz question: IAU classification scheme for comets, asteroids

Astronomy 210 Quiz 7, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

Listed below are 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 these qualifications are met by a comet?
(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) (None of the above choices.)

Section 30674
(A) : 23 students
(B) : 5 students
(C) : 0 students
(D) : 5 students
(E) : 1 student
(F) : 1 student
(G) : 6 students

Correct answer: (A)

Comets are typically irregularly shaped, and have eccentric and tilted orbits around the sun, and thus they have not cleared out nor dominate their orbits.

"Success level": 59% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.82

[Version 2]

Listed below are 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 these qualifications are met by an asteroid?
(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) (None of the above choices.)

Section 30676
(A) : 23 students
(B) : 5 students
(C) : 3 students
(D) : 16 students
(E) : 5 students
(F) : 6 students
(G) : 2 students

Correct answer: (A)

Asteroids orbit the sun, typically between Mars and Jupiter. However, they are irregularly shaped (if they were spherical, they would be dwarf planets), and they have not cleared out nor dominate their orbits (if they did, they would be planets).

This quiz question was also given in Fall semester 2008.

"Success level": 46% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.60

20100523

Astronomy quiz question: Venus' oceans?

Astronomy 210 Quiz 7, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

Where might the liquid water from the early oceans of Venus be today?
(A) Escaped into space.
(B) Trapped in sediments in the crust.
(C) Frozen underground.
(D) Completely evaporated.

Correct answer: (D)

Due to its proximity to the sun, Venus' thick atmosphere and strong greenhouse effect makes it much too warm for oceans to exist in liquid form.

Section 30674
(A) : 7 students
(B) : 4 students
(C) : 2 students
(D) : 28 students

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

20100522

Astronomy quiz question: origins of Earth's elements

Astronomy 210 Quiz 7, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

Fusion reactions in the core of another main-sequence star produced the:
(A) hydrogen in Jupiter's atmosphere.
(B) carbon in your body.
(C) gold and silver in Earth's crust.
(D) (None of the above choices.)

Correct answer: (B)

All "metals" (elements heavier than hydrogen) on Earth must have been produced by a previous generation star. Reactions in the cores of stars fuse hydrogen into heavier elements, notably carbon, and others up through iron. Type Ia supernovae and type II supernovae explosions will fuse elements heavier than iron, such as gold and silver.

Section 30674
(A) : 5 students
(B) : 9 students
(C) : 22 students
(D) : 5 students

"Success level": 27% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.09

[Version 2]

Fusion reactions in the core of the sun produced the:
(A) hydrogen in Jupiter's atmosphere.
(B) carbon in your body.
(C) gold and silver in Earth's crust.
(D) (None of the above choices.)

Correct answer: (D)

Since Earth was formed out of the same nebular disk as the sun, the elements in everything on Earth were produced from a previous generation of stars, and not from the fusion reactions in the core of the sun.

Section 30676
(A) : 12 students
(B) : 14 students
(C) : 23 students
(D) : 19 students

"Success level": 33% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.40

20100521

Physics quiz question: CERN proton Lorentz factor

Physics 205B Quiz 7, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 26.55(a)

The CERN Proton Synchrotron Booster in Switzerland (http://cdsmedia.cern.ch/img/CERN-Brochure-2008-001-Eng.pdf) is able to accelerate protons up to a speed of 0.916c, as measured from a stationary reference frame. What is the Lorentz factor γ for protons at this speed?
(A) 1.09.
(B) 1.19.
(C) 2.49.
(D) 3.45.

Correct answer: (C)

The Lorentz factor is given by:

γ = 1/sqrt(1 - (v/c)^2) = 1/sqrt(1 - (0.916c/c)^2) = 2.49.

Response (A) is 1/(v/c); response (B) is 1/(v/c)^2; response (D) is 1/sqrt(1 - (v/c)).

Student responses
Section 31988
(A) : 2 students
(B) : 3 students
(C) : 7 students
(D) : 0 students

Success level: 58%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.80

20100520

Physics quiz question: proton-to-neutron process

Physics 205B Quiz 7, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 29.1

Which decay mode turns a proton into a neutron?
(A) α.
(B) β-.
(C) β+.
(D) γ.
(E) (More than one of the above choices.)

Correct answer: (C)

A proton turns into a neutron by emitting a positron and a neutrino:

p -> n + e(+) + neutrino,

which is β+ decay. (This process could also be due to electron capture, which was not discussed in the scope of this course.)

Student responses
Section 31988
(A) : 0 students
(B) : 2 students
(C) : 8 students
(D) : 0 students
(E) : 2 students

Success level: 66%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.40

20100519

Physics quiz question: radioactive decay activity at a later time

Physics 205B Quiz 7, spring semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 29.37

(65,30)Zn has a half-life of 145 days. A sample of this material currently has an activity of 3.20×106 decays/s. The activity of this sample 1.16 days later will be:
(A) 256 decays/s.
(B) 2.76×103 decays/s.
(C) 1.25×104 decays/s.
(D) 4.00×105 decays/s.

Correct answer (highlight to unhide): (C)

The activity of a sample is given by:

R = R0·(1/2)(t/T1/2),

with R0, t, and T1/2 given, then:

R = (3.20×106 decays/s)·(1/2)(1.16×103 days/145 days) = 1.25×104 decays/s.

Response (A) is (2)(t/T1/2); response (B) is R0/t; response (D) is R0/8.

Student responses
Section 31988
(A) : 3 students
(B) : 2 students
(C) : 6 students
(D) : 1 student

Success level: 50%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.80

20100518

Physics midterm problem: unknown voltmeter reading

Physics 205B Midterm 2, spring semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 18.74

An ideal 15 V emf source is connected to ideal resistors and an ideal voltmeter, as shown at right. What is the reading of the voltmeter? Show your work and explain your reasoning using the properties of currents and potential differences, and Kirchhoff's rules and Ohm's law.

Solution and grading rubric:
  • p:
    Correct. From application of Kirchhoff's loop rule, voltmeter reading would be either 15 V - (6.0 Ω)·I6, or (1.0 Ω)·I1, or (5.0 Ω)·I5, with I6, I1, and I5 being the currents going through the 6.0 Ω resistor, 1.0 Ω light bulb, and 5.0 Ω resistor, respectively. Correctly finds one (or all) of the currents in this circuit by use of equivalent resistance, Ohm's law, and Kirchhoff's junction rule, and uses current(s) to determine the voltmeter reading.
  • r:
    Nearly correct, but includes minor math errors.
  • t:
    Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least finds equivalent resistance of circuit, and main current I6 = 2.2 A.
  • v:
    Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner.
  • x:
    Implementation of ideas, but credit given for effort rather than merit.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.

Grading distribution:
Section 31988
p: 4 students
r: 2 students
t: 3 students
v: 3 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 1230):

20100517

Physics midterm question: series light bulb powers

Physics 205B Midterm 2, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 18.21, 18.31

[10 points.] An ideal emf source is connected in series to two light bulbs, one of which is much brighter than the other. Which light bulb has the greater resistance? Explain your reasoning using the properties of currents and potential differences, and Kirchhoff's rules and Ohm's law.

Solution and grading rubric:
  • p = 10/10:
    Correct. Uses Ohm's law and power relations (P = I*delta(V) and/or I^2/R), along with recognizing that the same amount of current must pass through both these light bulbs in series to conclude that the bright light bulb has the greater resistance.
  • 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/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 31988
p: 6 students
r: 2 students
t: 3 students
v: 2 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 6886):

20100516

Physics midterm question: separating capacitor plates

Physics 205B Midterm 2, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 17.5, Problems 17.57, 17.58

[10 points.] A parallel plate capacitor is connected to a battery that supplies a constant potential difference. While the battery is still attached, the parallel plates are separated a little more. As the parallel plates are separated, will the charge increase, decrease, or remain constant? Explain your reasoning using the properties of capacitors.

Solution and grading rubric:
  • p = 10/10:
    Correct. As capacitance depends inversely on plate separation distance, increasing d will decrease C. Since the capacitor is still connected to a battery, the potential difference will remain constant, and due to C = Q/delta(V), as C decreases so will the charge Q.
  • 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. At least has complete/correct explanation for why C will decrease.
  • 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 31988
p: 4 students
r: 4 students
t: 0 students
v: 5 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1930):

20100515

Astronomy midterm question: Doppler redshifts and the expanding universe

Astronomy 210 Midterm 2, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[20 points.] Doppler shifts of galaxies is evidence that the universe is expanding. Explain what these Doppler shifts are, and how they are used to support the theory of an expanding universe.

Solution and grading rubric:
  • p = 20/20:
    Correct. Explains Doppler shifts show that light from galaxies are redshifted (stretched out to longer wavelength values) proportional to their distances, and thus indicate the universe is expanding (Hubble's law).
  • 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. Description of Doppler shifts missing/problematic, but adequate discussion of Hubble's law (or at least the general implication of an expanding universe based on galaxies receding), or vice versa.
  • 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 30674
p: 14 students
r: 4 students
t: 23 students
v: 1 student
x: 0 students
y: 2 students
z: 0 students

Section 30676
p: 16 students
r: 7 students
t: 32 students
v: 19 students
x: 1 student
y: 0 students
z: 1 student

A sample "p" response (from student 4747):

Another sample "p" response (from student 4733):

A refreshingly honest "y" response (from student 7272):

20100514

Astronomy midterm question: possible/impossible star cluster H-R diagrams

Astronomy 210 Midterm 2, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

[20 points.] Shown at right could be an H-R diagram of a star cluster, where all of these stars would have the same age. Discuss whether or not this H-R diagram is possible for a star cluster, and explain why, using the properties of stars and evolution times.

Solution and grading rubric:
  • p = 20/20:
    Correct. Understands that massive stars evolve faster than low-mass stars, such that massive stars reach the upper left of the main sequence first, spend the least amount of time there, and leave well before low-mass stars become main-sequence stars. Therefore the H-R diagram is not possible for a star cluster where the stars would have the same age.
  • r = 16/20:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Argument based on interpreting low-mass stars lying just off of the main sequence line as leaving the main sequence, which is yet to be observed given the age of the universe (while ignoring the presence of massive stars on the main sequence).
  • t = 12/20:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least understands how massive and low-mass stars evolve at different rates to get to (and leave) the main sequence.
  • 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 30674
p: 34 students
r: 1 student
t: 5 students
v: 3 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 1802):

Another sample "p" response (from student 0310):

Yet another sample "p" response (from student 0299), mentioning the "house party" analogy discussed in class:

A sample "v" response (from student 2569), noticing an apparent lack of medium-mass stars on the main sequence:

[Version 2]

[20 points.] Shown at right could be an H-R diagram of a star cluster, where all of these stars would have the same age. Discuss whether or not this H-R diagram is possible for a star cluster, and explain why, using the properties of stars and evolution times.

Solution and grading rubric:
  • p = 20/20:
    Correct. Understands that massive stars evolve faster than low-mass stars, such that massive stars reach the upper left of the main sequence first, spend the least amount of time there, and leave well before low-mass stars become main-sequence stars. Therefore the H-R diagram is possible for a star cluster where the stars would have the same (old) age.
  • 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 how massive and low-mass stars evolve at different rates to get to (and leave) the main sequence.
  • 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. Conclusion without substantive argument.
  • y = 2/20:
    Irrelevant discussion/effectively blank.
  • z = 0/20:
    Blank.
Grading distribution:
Section 30676
p: 35 students
r: 5 students
t: 4 students
v: 25 students
x: 7 students
y: 0 students
z: 0 students

A sample "p" response (from student 0264), also describing the cause of different evolution rates for massive and low-mass stars:

A sample "p" response (from student 8282), appealing to the "house party" analogy:

A sample "v" response (from student 1001), with a whimsical threat:

A brutally self-honest "x" response (from student ), in manga form:

20100513

Astronomy midterm question: Polaris vs. Vega; Deneb vs. Polaris

Astronomy 210 Midterm 2, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]

[20 points.] Consider the stars Polaris and Vega. Polaris is hotter, but its luminosity is dimmer; while Vega is cooler, but its luminosity is brighter. Discuss if it is possible for these stars to be the same size; if this is not possible, then determine which star (Polaris or Vega) must be larger. Support your answer using Wien's law and/or the Stefan-Boltzmann law.

Solution and grading rubric:
  • p = 20/20:
    Correct. Discusses how the Stefan-Boltzmann law (luminosity (brightness) proportional to size * (Temperature)^4) explains that the cooler of the two stars must be much larger in order to have a greater luminosity than the hotter star. Or may plot points on an H-R diagram, and shows that these two stars cannot lie along an equal radius diagonal.
  • 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 recognizes how the Stefan-Boltzmann law is applicable, but argument is garbled (e.g., has stars being the same size as possible).
  • v = 8/20:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Involves other factors such as distance, fusion rates, dimming by the interstellar medium, etc., typically confusing luminosity with apparent magnitude rather than absolute visual magnitude.
  • 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 30674
p: 27 students
r: 2 students
t: 11 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1415):

Another sample "p" response (from student 5239), referring to an H-R diagram:

Another sample "p" response (from student 6042), using a table of Stefan-Boltzmann law entries:

[Version 2]

[20 points.] Consider the stars Deneb and Polaris. Deneb is hotter and its luminosity is brighter; while Polaris is cooler and its luminosity is dimmer. Decide if it is possible for these stars to be the same size; if this is not possible, then determine which star (Deneb or Polaris) must be larger. Support your answer using Wien's law and/or the Stefan-Boltzmann law.

Solution and grading rubric:
  • p = 20/20:
    Correct. Discusses how the Stefan-Boltzmann law (luminosity (brightness) proportional to size * (Temperature)^4) explains that the cooler of the two stars must be much larger in order to have a greater luminosity than the hotter star. Or may plot points on an H-R diagram, and shows that these two stars may lie along an equal radius diagonal.
  • 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 recognizes how the Stefan-Boltzmann law is applicable, but argument is garbled (e.g., has stars being the same size as possible).
  • v = 8/20:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Involves other factors such as distance, fusion rates, dimming by the interstellar medium, etc., typically confusing luminosity with apparent magnitude rather than absolute visual magnitude.
  • 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 30676
p: 38 students
r: 1 student
t: 27 students
v: 8 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 9033):

A sample "p" response (from student 1007):

20100512

Astronomy current events question: Mars rover 3D camera

Astronomy 210L, Spring 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!)
Tim Hornyak, "James Cameron Building 3D Cam for Mars Rover," April 29, 2010
http://news.cnet.com/8301-17938_105-20003827-1.html
James Cameron, Academy Award winning director of Avatar, is working with NASA to develop:
(A) remote controlled robots for dangerous spacewalk missions.
(B) a documentary on living aboard the International Space Station.
(C) virtual reality technology to train astronauts.
(D) a 3D camera for the next Mars rover.
(E) computer animations of lifeforms that may exist on exoplanets.

Correct answer: (D)

Student responses
Sections 30678, 30679, 30680
(A) : 0 students
(B) : 5 students
(C) : 3 students
(D) : 45 students
(E) : 3 students

20100511

Astronomy current events question: Lunkhod 1 retroreflector

Astronomy 210L, Spring 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, "Lunokhod 1 Retroreflector Found," April 27, 2010
http://www.astronomy.com/asy/default.aspx?c=a&id=9804
NASA has rediscovered the positions of the Russian Lunakhod 1 retroreflector on the surface of the moon. This retroreflector will be used to study:
(A) how slowly the moon is moving away from Earth.
(B) secrets of early Russian space technology.
(C) prolonged effects of solar wind on metal alloys.
(D) the very sparse atmosphere of the moon.
(E) the slow formation of ice on lunar surfaces.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 32 students
(B) : 0 students
(C) : 13 students
(D) : 4 students
(E) : 6 students

20100510

Astronomy current events question: asteroid 24 Themis

Astronomy 210L, Spring 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, "Ice Lurks in Asteroid's Cold Heart," April 29, 2010
http://www.astronomy.com/asy/default.aspx?c=a&id=9811
Observations from the NASA Infrared Telescope Facility have revealed the presence of __________ on asteroid 24 Themis.
(A) radioactive elements.
(B) dark matter.
(C) water ice and carbon-based organic compounds.
(D) fragments of the large impact that created Earth's moon.
(E) solar neutrinos.

Correct answer: (C)

Student responses
Sections 30678, 30679, 30680
(A) : 4 students
(B) : 3 students
(C) : 45 students
(D) : 3 students
(E) : 0 students