20151215

Astronomy quiz question: interstellar gas and dust in the Milky Way

Astronomy 210 Quiz 7, fall semester 2015
Cuesta College, San Luis Obispo, CA

Interstellar gas and dust in the Milky Way prevents most of its __________ from being visible from Earth.
(A) stars.
(B) dark matter.
(C) radio waves.
(D) neighboring galaxies.

Correct answer (highlight to unhide): (A)

Interstellar gas and dust blocks visible light from stars, while typically not affecting longer wavelength forms of light such as radio waves. Dark matter is not visible already, and clear views of our neighboring galaxies can be seen above and below the gas and dust in the disk of the Milky Way.

Section 70158
Exam code: quiz07srrH
(A) : 32 students
(B) : 1 student
(C) : 0 students
(D) : 6 students

Success level: 83% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.62

Section 70160
Exam code: quiz07nM0r
(A) : 18 students
(B) : 1 student
(C) : 1 student
(D) : 6 students

Success level: 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64

Astronomy quiz question: current status of type Ia supernova seen tonight

Astronomy 210 Quiz 7, fall semester 2015
Cuesta College, San Luis Obispo, CA

A type Ia supernova in a distant galaxy seen in Earth's night sky tonight is currently a:
(A) protostar.
(B) white dwarf.
(C) planetary nebula.
(D) (None of the above choices.)

Correct answer (highlight to unhide): (D)

The finite speed of light means that it takes time for light from distant objects to reach the Earth. Thus looking at an object a given number of light years away means that it appears as it did that same number of years in the past. Since a type Ia supernova is the entire destruction of a white dwarf after rapidly stealing hydrogen from its companion star, then by the time observers on Earth see this explosion tonight, the white dwarf had already exploded in the past, and subsequently (and currently) nothing is left at that location.

Section 70158
Exam code: quiz07srrH
(A) : 8 students
(B) : 10 students
(C) : 11 students
(D) : 10 students

Success level: 29% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.62

Section 70160
Exam code: quiz07nM0r
(A) : 5 students
(B) : 8 students
(C) : 4 students
(D) : 8 students

Success level: 36% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.57

20151211

Physics quiz archive: temperature, thermal equilibrium, heat transfer

Physics 205A Quiz 7, fall semester 2015
Cuesta College, San Luis Obispo, CA
Sections 70854, 70855, 73320, version 1
Exam code: quiz07zSOL



Sections 70854, 70855, 73320 results
0- 6 :   * [low = 3]
7-12 :   *****
13-18 :   *****************
19-24 :   ****************************** [mean = 21.2 +/- 5.6]
25-30 :   **************** [high = 30]

Astronomy quiz archive: Milky Way, cosmology

Astronomy 210 Quiz 7, fall semester 2015
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz07srrH


Section 70158
0- 8.0 :   *** [low = 4.0]
8.5-16.0 :   **********
16.5-24.0 :   *********** [mean = 21.5 +/- 9.3]
24.5-32.0 :   *********
32.5-40.0 :   ****** [high = 40.0]


Section 70160, version 1
Exam code: quiz07nM0r


Section 70160
0- 8.0 :   *** [low = 4.0]
8.5-16.0 :   ******
16.5-24.0 :   ******* [mean = 20.7 +/- 9.6]
24.5-32.0 :   *******
32.5-40.0 :   ** [high = 40.0]

20151209

Online reading assignment: origin of life, are we alone? (SLO campus)

Astronomy 210, fall semester 2015
Cuesta College, San Luis Obispo, CA

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

The following questions were asked on reading textbook chapters and previewing presentations on the origin of life, a "Here Is Today" timeline, LEGO® washing tips and the extraterrestrial hypothesis.


Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"The idea that there could be other civilizations makes me geek out!"

"That life started in the ocean. That is the first time that I have ever heard that idea. It's very hard to imagine the rocks from Australia that are more than 3.4 billion years old!"

"I really liked the 'Here is Today' timeline because it is cool visually seeing things mapped out like that."

"SETI/BETI."

"I found the Lego experiment really interesting. It's amazing that it works. It makes an excellent model for the formation of complex molecules."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I'm very confused by the Drake equation because the book says that some of the factors can be estimated, but the last factor cannot. If the last factor can't be certain, how does the equation solve out then?"

"I find it confusing that people believe that crop circles are from 'aliens' simply because they think they have nothing or no one else to blame it on."

"I don't really understand how the atoms turn into the chemicals that we have today."

"Deciphering the Aericibo message is really confusing."

Briefly describe a difference between life and non-living things.
"Non-living things are just raw elements."

"A living thing has the ability to copy its DNA. A living thing is also able to adapt to its surrounding environment for survival."

"Life manipulates its environment to survive and replicate, non-living things do not."

"Life is something that changes its environment in some way and reproduces."

How important is it to you to know whether or not there may be life elsewhere other than on Earth?
Unimportant.  [1]
Of little importance.  ******* [7]
Somewhat important.  ******* [7]
Important.  **** [4]
Very important.  ***** [5]

Briefly explain your answer regarding the importance of knowing whether there may be life elsewhere other than on Earth.
"As far as I'm concerned there is absolutely life elsewhere, I'd even say there is absolutely intelligent life. The universe is a really big place, there's no we life only happened once. Actually knowing of it elsewhere would be nice though."

"Knowing whether or not there is life on another planet is only important to me because of curiosity. It doesn't change what I do on a daily basis but I think most people are intrigued by the idea that there could be intelligent life somewhere else."

"I would like to know, but even if we found life, there would be no way for us to get there."

"I am sure if this was discovered there would be many benefits and be important, but until that happens I do not find it very important because it is not affecting my everyday life, or the lives of those around me."

"Finding evidence of life elsewhere on earth will tip the Drake equation parameters more to the optimistic side and provide evidence that life can flourish given the right environment."

"It would validate our existence as well as expand it. It would mean we're not a fluke."

"In such a vast universe I think that it would be shocking if the only living things were contained on one little planet in the corner of it all. I think that there is definitely life elsewhere and I have always been fascinated by the thought of it because it puts a whole new perspective on our existence."

"To me, I believe if it was really important it would've appeared already before us and considering that nothing has become a threat to us yet I am not concerned although I do believe we should prepare for anything that happens and for all we know there could be good or bad life forms out there but considering we don't have the means right now to know what that is and no one's bothering us out there I am not concerned."

"At some point the human race may need a new home to survive, so it would be important to find planets that could support life."

"It's of little importance mainly because right now, we have too many problems here on Earth to deal with and spend money fixing. It's not important to me to know if there's life elsewhere; there's life here already and we as people aren't doing a great job of nurturing it."

Which type of star would be least likely to have a planet that could support life?
Massive.  [17]
Medium-mass.  [1]
Low-mass (red dwarf).  [5]
(Unsure/guessing/lost/help!)  [1]

Briefly explain your answer to the previous question (type of star least likely to have a planet that could support life).
"A massive star would be least likely to have a planet that could support life because massive stars die the quickest out of all of them."

"If life on Earth took nearly a billion years to arise, then a short-lived massive star would die long before any of the beginnings of life could form on its planet."

"I think a red dwarf would be least likely to have a planet because it's mass is smaller so it's gravitational pull is also smaller. This means it is less likely for a planet to get caught in orbit around it."

Describe what the Drake equation is used for.
"To understand and place constraints on the possibility of life, and the general trend from less to more restrictive conditions."

"It's an equation used to estimate the number of technologically advanced civilizations there are in the Milky Way."

"It's confusing, couldn't understand its exact purpose."

In your opinion, how plausible is it that the Chilbolton message is a reply from extraterrestrials?
Implausible.  ****** [6]
Not very plausible.  *********** [11]
Somewhat plausible.  **** [4]
Very plausible.  * [1]
(Unsure/guessing/lost/help!)  ** [2]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Can we take our final early if we can, like on another day before Wednesday or no?" (Let's talk.)

"Do you think there is enough evidence today to support the notion that there might be life on another planet?" (No, not yet. Maybe soon.)

"Man, if there are other living things out there I would want to know what they find cool, like if they think Crocs could ever be cool."

"Can I have a telescope for Christmas?" (That depends--have you been good this year?)

"This whole chapter was super-fascinating! Stoked to talk about it in class." (You're stoked? I'm stoked. #astronomystoke)

"I have truly learned from this class and enjoyed every minute of it, thank you for being an awesome professor, P-dog."

20151208

FCI post-test comparison: Cuesta College versus UC-Davis (fall semester 2015)

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

Cuesta College
Physics 205A
fall semester 2015    
UC-Davis
Physics 7B
summer session II 2002
N56 students*63 students*
low  4  3
mean    13.6 ± 6.512.9 ± 5.5
high2826

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

Student's t-test of the null hypothesis between Cuesta College FCI post-test scores and UC-Davis FCI post-test scores results in p = 0.51 (t = 0.657, sdev = 5.95, degrees of freedom = 137), thus there is no significant difference between Cuesta College and UC-Davis FCI post-test scores.

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

Physics 205A fall semester 2015 sections 70854, 70855, 73320
<initial%>= 33% ± 18% (N = 85)
<final%>= 45% ± 22% (N = 63)
<g>= 0.19 ± 0.23 (matched-pairs); 0.18 (class-wise)

Student's t-test of the null hypothesis for Cuesta College FCI pre-test scores versus post-test scores results in p = 0.0004 (t = -3.60, sdev = 5.91, degrees of freedom = 146), thus there is a statistically significant difference between Cuesta College FCI pre-test and post-test scores.

This Hake gain is comparable to previous semesters' results for algebra-based introductory physics at Cuesta College (0.17-0.33), but also slightly higher than previous gains for algebra-based introductory physics at UC-Davis (0.16), and for calculus-based introductory physics at Cuesta College (0.14-0.16), as discussed in previous postings on this blog.

Notable about this Physics 205A class at Cuesta College since fall semester 2014 is the requirement that students read and answer questions on the textbook and lecture slides before coming to lecture (in a "flipped classroom"), instructor discussion in-class based on answering student questions and concerns submitted online previous to lecture, in-class problem-solving sessions ("lecture-tutorials," including ranking tasks, and a brief written explanation of a selected question submitted by each student every lecture), open-ended labs, and the continuing use (since fall semester 2011) of flashcards rather than electronic response system "clickers" (Classroom Performance System, einstruction.com), to engage in "think-pair-share" (peer-instruction).

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

Previous FCI results:

FCI pre-test comparison: Cuesta College versus UC-Davis (fall semester 2015)

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

Cuesta College
Physics 205A
fall semester 2015    
UC-Davis
Physics 7B
summer session II 2002
N85 students*76 students*
low 2 2
mean    10.0 +/- 5.5 9.1 +/- 4.3
high2427

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

Student's t-test of the null hypothesis results in p = 0.19 (t = 1.31, sdev = 4.93, degrees of freedom = 159), thus there is no significant difference between Cuesta College and UC-Davis FCI pre-test scores.

Later this semester (fall 2015), a comparison will be made between Cuesta College and UC-Davis FCI post-tests, along with their pre- to post-test gains.

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

Previous FCI results:

Online reading assignment: origin of life, are we alone? (NC campus)

Astronomy 210, fall semester 2015
Cuesta College, San Luis Obispo, CA

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

The following questions were asked on reading textbook chapters and previewing presentations on the origin of life, a "Here Is Today" timeline, LEGO® washing tips and the extraterrestrial hypothesis.


Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"I thought the possibility of other planets sustaining life was interesting, because there are so many other galaxies out there. So, it should be possible."

"I don't really have anything in this chapter I found interesting."

"That molecules combine together to make other things. I knew this, but it is still interesting to me that atoms could make real things we live off of."

"I now realize I'm really exaggerating when I say, 'eon.' An eon is a very long time!"

"That planets similar to ours have been discovered, and that they have a chance of having life on them."

"The Arecibo message because it reminds me of shorthand and ASL and other foreign languages. If you don't know the meaning of what you're seeing or hearing, it's secretive because you can't understand the message."

"Talking about living and non living things I'd pretty cool. I'm interested in that type of stuff."

"I thought that video of the crop circles was cool, it's pretty crazy if you think about it how percise everything was cut."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"The timeline of life. It doesn't seem reasonable."

"The Drake equation was pretty confusing. And the variables needed in the equations are somewhat confusing."

"Everything with Drake equation was confusing, but I think it's just because I only see letters in the equation rather than numbers."
"Not confusing just think this is a lot of BS."

"I don't really know anything about the Chilbolton message."

"Simple molecules make energy? I don't get it."

"The Miller experiment."

"Carbon molecular chains."

Briefly describe a difference between life and non-living things.
"Life is a living, breathing object. Non-living things are just objects."

"I am living because I require air, my cell phone doesn't."

"Living things are made up of life and exhibit characteristics of life/"

"Life: smallest unit classified as life are cells. Non-living: A mass of just matter (rocks are really good examples since they're both on in space and everywhere throughout Earth)."

"Living things can learn to adapt to their environment (or change it to where the enviroment changes for them) while non- living things can't do this."

"Living things have enough information to manipulate its environment, make new generations of itself by protecting itself with a cell wall and growing larger and being able to divide itself into multiple copies of itself. and nonliving things cannot do that."

How important is it to you to know whether or not there may be life elsewhere other than on Earth?
Unimportant.  * [1]
Of little importance.  *** [3]
Somewhat important.  *** [3]
Important.  ***** [5]
Very important.  ***** [5]

Briefly explain your answer regarding the importance of knowing whether there may be life elsewhere other than on Earth.
"Even without validation I'm fairly positive that we can't be the only planet with life forms (single celled or otherwise). Of all the galaxies, are we so cynical to think that we are the only ones? We are but a chance, and there must be other 'chances' out there, somewhere."

"I am a Christian--I believe that God created the Heavens and Earth with the universe so big I would not be surprised if God made us a sibling species I would treat them like anyone else."

"Knowing if theres life elsewhere has always been a question I've been dying to know. I have always thought about what it is like on another life planet and wondered if it is the same type of life we are living. I've thought about this so many times and hope I can know the answer before I die."

"I like to learn new things."

"Discovery and travel are the big and broad categories that most opinions fall under when wanting to go to another planet. Here are the a few reasons why that more exploration of the notion is unwise: (1) Earth has yet to be Appropriately documented geographically, historically, and demographically (examples: deep dark water ocean life). (2) Most people never even experience even a tenth of the world for themselves."

"I need to know if there are aliens so that if there is I can assemble a super hero group like the Avengers to protect us."

Which type of star would be least likely to have a planet that could support life?
Massive.  ******* [7]
Medium-mass.  ** [2]
Low-mass (red dwarf).  **** [4]
(Unsure/guessing/lost/help!)  **** [4]

Briefly explain your answer to the previous question (type of star least likely to have a planet that could support life).
"Because a low mass star probably wouldn't be able to produce enough light and heat?"

"Massive because they don't last long enough to have a planet."

"The low-mass star would be more calm."

Describe what the Drake equation is used for.
"The Drake equation is used to multiply a number of factors that reflect conditions for a technological civilization to arise."

"Derived by Frank Drake the Drake equation estimates arithmetically the number of technological civilizations per galaxy."

"There factors that we need to consider to help us see if there's a chance that life can exist on another planet."

In your opinion, how plausible is it that the Chilbolton message is a reply from extraterrestrials?
Implausible.  **** [4]
Not very plausible.  ***** [5]
Somewhat plausible.  **** [4]
Very plausible.  [0]
(Unsure/guessing/lost/help!)  **** [4]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Will the quiz or the final make my grade get lower or can I only go up from here?" (It can only go up (or remain the same), because your grade is determined by accumulated points, not from a percentage.)

"Do you believe the Chilbolton message is from extraterrestrials?" (No, just from neighboring radio telescope astronomers with a sense of humor.)

"Not really a question just comment on communication. Assuming other lifeforms are communicating with us, as lifeforms with intelligence we have a disjointed system of communication with other humans which we interpret incorrectly many times. We also don't effectively communicate with other forms of life on the planet as well, such as with teaching chimpanzees sign language, which is not their natural interaction. We have them learn our ways then in turn study them. Many opportunities for things 'lost in translation.'"

"Are you looking forward to the semester ending as much as we are?" (Yes. Mrs. P-dog and I are going to look at some cool things in the desert that were most certainly not created by aliens.)

"What if someone in this class is an alien?" (Sounds like something an alien would say. #justsaying)

20151207

Online reading assignment: heat transfer applications

Physics 205A, fall semester 2015
Cuesta College, San Luis Obispo, CA

Students have a bi-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.

The following questions were asked on reading textbook chapters and previewing a presentation on heat transfer applications.

Selected/edited responses are given below.

Describe what you understand from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically demonstrate your level of understanding.
"I understand conduction, convection, and radiation pretty well now."

"That we will be choosing one of these products to test in lab."

"People will say just about anything in hopes of selling a product, whether it is true or not. And that the properties of heating and cooling objects are much simpler to understand when put into situations involving food. I like food."

"I understand that we will be testing different claims by companies that provide goods for the consumer. The challenge is for us to decipher whether these claims are plausible or not."
"I don't know. The presentation never gave me any facts, just questions."

"I understand that the need for bevergaes to be the perfect drinking temperature is paramount. The main methods used to obtain this optimum temperature utilize conduction--the transfer of heat from warm objects to cooler ones through physical contact."
"There are different products that have been made that take advantage of the various heat transfers. However, not all of the products are efficient as they claim to be."

"The presentation preview made a few claims about different products that are supposed to heat or cool different products at a faster speed than they would naturally. The claims seemed to work by making the particular thing reach thermal equilibrium with whats being put in it or on it (like the 'stones' in the coffee)."

"The Cooper Cooler™ is able to chill beverages much quicker than a freezer or a refrigerator (90× faster than a refrigerator and 40× faster than a freezer)."

"I learned some new material reading the presentation, especially about the coffee joulies. It's interesting how they absorb the heat from the coffee and as it begins to cool down it releases more heat keeping it at a constant until the heat is out."

"A space blanket works in a cool conditions, which it reflects heat radiated by the body back into the body."

Describe what you found confusing from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically identify the concept(s) that you do not understand.
"How those coffee beans could keep the coffee warm for 2 hours. I am very skeptical of this. I would like to know more about the physics involved here."

"This was just kind of review."

"I don't think I found anything that confusing really."

"I find most things in physics confusing."

"I was a little confused about which form of heat transfer was responsible for the temperature change in each scenario. I can't decide if the Coffee Joulies™ would cool through conduction or convection, for example."

The primary heat transfer process that the Cooper Cooler™ uses to chill beverages is:
conduction.  ************************ [24]
convection.  **************************** [28]
radiation.  ** [2]
(Unsure/guessing/lost/help!)  **** [4]

How plausible do you think these claims for the Cooper Cooler™ are?
(Only modal responses shown.)
"The Cooper Cooler™ can chill a soda in one minute": somewhat plausible [52%]
"Because it's spinning and not shaking your carbonated beverages, you don't have to worry about them exploding": somewhat plausible [40%]

The primary heat transfer process that the Coffee Joulies™ uses to moderate and maintain coffee temperatures is:
conduction.  *********************************** [35]
convection.  ************** [14]
radiation.  ****** [6]
(Unsure/guessing/lost/help!)  *** [3]

How plausible do you think these claims for Coffee Joulies™ are?
(Only modal responses shown.)
"One 'bean' for every four ounces of coffee cools right down to 140° in a few seconds": somewhat plausible [52%]
"Keeps coffee at 140° for two full hours": not very plausible [34%]

The primary heat loss process that any blanket (regardless of type) should prevent in typical "emergency survival conditions" (on Earth) is:
conduction.  ********** [10]
convection.  **** [4]
radiation.  ***************************************** [41]
(Unsure/guessing/lost/help!)  *** [3]

How plausible do you think heavy-duty garbage bag material will be just as effective as a space blanket for typical "emergency survival conditions" on Earth?
Implausible.  ********* [9]
Not very plausible.  ************* [13]
Somewhat plausible.  ************* [23]
Very plausible.  ********* [9]
(Unsure/guessing/lost/help!)  **** [4]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"How does spinning not induce CO2 formation the way shaking does in a soda? How do the Coffee Joulies™ cool the drink immediately to 140° F?"

"Coffee Joulies™? I mean, if you don't drink your coffee by the time it's room temperature, you're doing something wrong."

"I am itching to go snowboarding!" (Just don't be one of those snowboarders that sits down in the middle of the run for a smoke break. I hate those guys.)

"Found this chapter to be very understandable--can we add some conceptual dialogue to these question for class tomorrow?"

"Can we go over these in class? I really have no idea if I'm doing these even remotely correct."

"I found a kitten in the dumpster and decided to keep him. I guess you can call me Captain America now." (That, or a dumpster diver. Captain Dumpster Diver. #iwillhughimandpethimandsqueezehim #andiwillnamehimgeorge)

"I secretly can't wait till the holidays are over. I want to commit to my regular eating and workout schedule again." (#goodgradesgoodsleepgoodhealth #chooseonlytwo)

20151206

Astronomy current events question: LkCa 15 protoplanet formation

Astronomy 210L, fall semester 2015
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!)
Bjorn Carey, "Stanford Astronomers Observe the Birth of an Alien Planet" (November 18, 2015)
news.stanford.edu/pr/2015/pr-proto-planet-forming-111815.html
Observations of __________ provide evidence of protoplanet formation around the star LkCa 15.
(A) glowing hydrogen gas.
(B) gamma ray emissions.
(C) reflected radio waves.
(D) spiral dust patterns.
(E) gravitational lensing.

Correct answer: (A)

Student responses
Sections 70178, 70186
(A) : 11 students
(B) : 0 students
(C) : 5 students
(D) : 12 students
(E) : 6 students

Astronomy current events question: Triangulum II dwarf galaxy dark matter

Astronomy 210L, fall semester 2015
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!)
Lori Dajose, "Dark Matter Dominates in Nearby Dwarf Galaxy" (November 18, 2015)
caltech.edu/news/dark-matter-dominates-nearby-dwarf-galaxy-48790
Dark matter in the nearby Triangulum II dwarf galaxy was measured by observing its:
(A) heavy metals.
(B) stars' motions.
(C) pulsar timings.
(D) gamma ray emissions.
(E) neutrino decays.

Correct answer: (B)

Student responses
Sections 70178, 70186
(A) : 3 students
(B) : 15 students
(C) : 4 students
(D) : 11 students
(E) : 1 student

Astronomy current events question: repeat of hecil505 "Residual" supernova

Astronomy 210L, fall semester 2015
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!)
Patrick Kelly, Steve Rodney, Tommaso Treu, and Mathias Jäger, "Astronomers Get Once-in-a-Lifetime opportunity to Predict Supernova" (November 13, 2015)
spacetelescope.org/announcements/ann1526/
NASA's Hubble Space Telescope will observe a repeat next year of the heci1505 "Refsdal" supernova observed last year, due to its light being distorted by the gravity of:
(A) a galaxy cluster.
(B) a wormhole.
(C) emission nebulae.
(D) antimatter.
(E) tachyon particles.

Correct answer: (A)

Student responses
Sections 70178, 70186
(A) : 20 students
(B) : 0 students
(C) : 7 students
(D) : 4 students
(E) : 3 students

20151202

Online reading assignment: Milky Way history, big bang clues (SLO campus)

Astronomy 210, fall semester 2015
Cuesta College, San Luis Obispo, CA

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

The following questions were asked on reading textbook chapters and previewing presentations on the history of the Milky Way and big bang clues, a comic strip adaptation of of Neil deGrasse Tyson's "The Most Astounding Fact" 2008 interview for TIME magazine, and Minute Physics' video explanation of Olbers' paradox.


Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"I like the idea that when you're looking at a star that's light years away, the star could look completely different, or could be dead already."

"Learning about metals and how they came from stars was cool! That was personally the most interesting thing for no good reason. :)"

"The fact that the big bang was not created with a center that it was created everywhere. I thought this was interesting because that was always what I thought it started from."

"I enjoyed the explanation of look-back time and how we are not seeing the edge of space but the edge of time."

"The part about the edge of space was really interesting to me. I have always wondered about infinity and if the universe had an end so it was interesting reading about it and how the universe has a finite age."

"That the universe is not infinite and has an edge in all directions. i though this was interesting b/c i just thought space was never ending and it went on and on."

"We see the star Deneb 1,400 years in the past. That seems so crazy to me that you can look at something with your naked eye and actually be looking at something from the past."

"I enjoyed reading about the Milky Way, and the history behind it. Also how the universe started out with only hydrogen, and stars gathered this to form metals."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Look-back time was confusing b/c reading something doesn't mean that i understand. i will need more explanation on this."

"Something I found confusing was the edge of time and how when we see an edge it is an edge of time and not an edge of space. That seems hard for me to wrap my head around."

"Why the night sky is dark. I was not able to put it together while reading."

"I'm having a hard time with the metal poor or metal rich categories as I think I may be mixing up the disk or halo."

"I found the part of the look-back time was confusing. I've heard the part that the stars we see are really much older than that what we see from the naked eye, but its hard to comprehend that a star I'm looking at in the sky is really from 1,400 years ago."

"If the universe is finite, what's beyond the universe? I guess I just didn't get the gaps and edges thing yet."

"If the universe is expanding, shouldn't things not be moving at the same speed."

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [52%]
Metals (elements heavier than hydrogen and helium): increased [81%]

The outermost layers of __________ are more abundant in metals (elements heavier than hydrogen and helium).
extremely old stars that formed a long time ago.  *** [3]
young stars that formed very recently.  ******************* [19]
(There is a tie.)  [0]
(Neither, as stars cannot have metals.)  * [1]
(Unsure/guessing/lost/help!)  **** [4]

Indicate what produced these elements.
(Only correct responses shown.)
Helium in the sun's core: the sun [37%]
Carbon in your body: another star, in the past [52%]
Calcium in your bones: another star, in the past [56%]
Iron in your blood: another star, in the past [59%]
Gold and silver from mines: another star, in the past [56%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"If when we are looking at stars through telescopes we are looking back in time at how they were millions of years ago, is it possible that they no longer exist at this exact point in time and that we are just seeing them as they were in the past?" (Yes.)

"Are there essays on the final?" (Yes, just like the midterms.)

"Where did the original atoms come from that were involved in the big bang?" (Those atoms (primarily hydrogen) were converted from energy. Then subsequent generations of stars fused that hydrogen into every other type of atom listed in the periodic table.)

Online reading assignment: heat transfers

Physics 205A, fall semester 2015
Cuesta College, San Luis Obispo, CA

Students have a bi-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.

The following questions were asked on reading textbook chapters and previewing a presentation on heat transfers.


Selected/edited responses are given below.

Describe what you understand from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically demonstrate your level of understanding.
"I clearly understand the heat transfers of convection, conduction and radiation. I also understand the difference between blackbody, which is good at absorbing heat and emitting heat. Where as silver body is good at reflecting light but poor at absorbing heat."

"I understand that heat conduction is where heat is transferred through an object. Also, that convection is the transport of heat via circulating air. And that radiation is where heat is transported in the form of light."

"Conduction is heat transferred through an object. Power is the measurement of this transferred heat per unit time. Expressed either in joules/second or watts. Resistance is the measurement of how difficult this transfer of heat is. It is proportional to the materials thickness. Convection is the transfer of heat through masses of moving air. Radiation is the transfer of hear through light. Objects that are good at absorbing radiation heat must also be good at emitting or radiating heat."

"Not much."

Describe what you found confusing from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically identify the concept(s) that you do not understand.
"Stefan's law. I understand what the law is, I'm just unclear about using it in a problem."

"No specific confusion yet, though I'm expecting to run into more after class discussion and examples."

"The only concepts I don't understand are the equations themselves. Everything else is a matter of practice. The concepts can be a little confusing, but I understand the basics."

"The language in describing the concepts is frustrating."

"I'm confused about the whole online presentation. There is a lot of equations with a whole bunch of variables that it is making it impossible to understand."

"What the constants represent in these equations and why they're important. Why does power use κ and convection use σ?"

In order to maximize the thermal resistance of these exterior walls, should the following parameters be minimized, maximized (or has no effect)?
(Only correct responses shown.)
insulation thickness d: maximize [89%]
insulation conductivity κ: minimize [67%]
Total surface area A exposed to the outdoors: minimize [77%]

In order to minimize the amount of heat flowing per time through these exterior walls, should the following parameters be minimized, maximized (or has no effect)?
(Only correct responses shown.)
temperature difference ∆T between indoors and outdoors: minimize [75%]
thermal resistance R of the walls: maximize [84%]

For these two Leica M cameras, if they are both cooler than the surrounding environment, both will begin to heat up by absorbing radiative heat (say, from the sun). The __________ model have a faster rate of heat absorbed per time.
black.  ********************************************** [46]
silver.  **** [4]
(There is a tie.)  *** [3]
(Unsure/guessing/lost/help!)  **** [4]

For these snowboarders, if they are warmer than the surrounding environment, they will begin to cool down by emitting radiative heat (say, to the overcast sky and the snowy landscape). The snowboarder wearing the __________ jacket will have a faster rate of heat radiated per time.
black.  *********************************** [35]
silver.  ***************** [17]
(There is a tie.)  *** [3]
(Unsure/guessing/lost/help!)  ** [2]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I am confused why black releases heat faster but absorbs heat fast as well. How could this happen?" (Radiation/absorption is a two-way street. It would be very odd for a material to absorb heat, but not be able to radiate heat. That material would basically start absorbing all the heat in the universe yet not be able to re-release it, thus becoming infinitely hot, while the rest of the universe reaches absolute zero. So it's a good thing that a blackbody is an efficient radiator as well as being an efficient absorber.)

"Why would they paint the entire SR-71 Blackbird black if it causes the entire object to absorb heat quicker? Wouldn't it be more effective to only paint the area around the engines black to radiate heat and the rest silver to resist an increase in temperature?" (That would be true if the engines were the only hot part of the SR-71 Blackbird and that heating up from absorbing sunlight were important factors, but due to how fast it flies, the amount of air continuously ramming into it heats the whole aircraft up such that radiating heat from all of its black-painted surfaces is the only way to make sure the entire thing doesn't fall apart from melting.)

"Why do snowboarders and skiers wear tinted goggles?" (Bigger question: why do snowboarders take smoke breaks right in the middle of a run? #whatsupwiththat)

"Are we going to have to test our calligraphy skills and write that fancy script "P" every time we use Fourier's law or Stefan's law?" (Yes, unless you promise not to confuse "power P" with "pressure P," momentum "p," or "density ρ.")

"The melting chocolate bunnies was somewhat disturbing."

"Starting to wreck this class! #yolo"

20151201

Online reading assignment: Milky Way history, big bang clues (NC campus)

Astronomy 210, fall semester 2015
Cuesta College, San Luis Obispo, CA

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

The following questions were asked on reading textbook chapters and previewing presentations on the history of the Milky Way and big bang clues, a comic strip adaptation of of Neil deGrasse Tyson's "The Most Astounding Fact" 2008 interview for TIME magazine, and Minute Physics' video explanation of Olbers' paradox.


Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"It was pretty sick reading about how the elements of the universe have changed over the course of many years."

"When you look at a start or galaxy from lightyears away you are looking at how it was not how it is now."

"The big bang theory because I have always been curious on what it means/what it was."

"I think that metallification is a cool way to find out which stars are older than others."

"For every light year, it is equivalent to an entire year of look-back time. I've always wondered how far back we were seeing but never knew how it worked."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"What I found confusing was in the Milky Way, there is a broad distinction between stars in the halo, and stars in the disk. I can't wrap my head around how scientists know that they must be the Milky Way's first generation stars."

"Something I found confusing is how we can tell how the Milky Way was formed by looking at the metals?"

"How astronomers know that the universe if finite and not infinte. How are they able to figure that out?"

Indicate how the amount of these elements in the universe have changed over time.
(Only correct responses shown.)
Hydrogen: decreased [28%]
Metals (elements heavier than hydrogen and helium): increased [67%]

The outermost layers of __________ are more abundant in metals (elements heavier than hydrogen and helium).
extremely old stars that formed a long time ago.  ****** [6]
young stars that formed very recently.  ************ [12]
(There is a tie.)  [0]
(Neither, as stars cannot have metals.)  [0]
(Unsure/guessing/lost/help!)  [0]

Indicate what produced these elements.
(Only correct responses shown.)
Helium in the sun's core: the sun [28%]
Carbon in your body: another star, in the past [33%]
Calcium in your bones: another star, in the past [39%]
Iron in your blood: another star, in the past [39%]
Gold and silver from mines: another star, in the past [22%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Help us."

"Is this material also on the final?" (Yes. Also on the next quiz.)

"Is there still any extra credit available?" (Yes.)

"The universe is getting dirtier as the new generations of stars burst--does this affect Earth?" (Yes, it already has--our sun is a third-generation star, and it and our solar system formed from the leftover hydrogen and the metals produced by two previous generations of supernovae. It's quite ironic that the name of our planet is literally, "Dirt.")

"Why do stars fall into a black hole instead of being sucked in?" (Think of it this way: Earth doesn't suck. When you jump up off the ground, its gravity pulls on you such that you fall back down towards Earth. Similarly with black holes--they also don't suck--because of their gravity, they pull on you such that you fall in towards them. #everythingsucks)

"I AM SO HAPPY AT HOW WELL I DID ON MIDTERM 2!!!!!!" (I KNOW--I'M SO HAPPY FOR YOU TOO!!!!! #bringiton #itsalreadybeenbroughten)