20170224

Astronomy current events question: comets falling into star HD 172555

Astronomy 210L, spring semester 2017
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!)
Donna Weaver, Ray Villard, and Carol Grady, "Hubble Detects 'Exocomets' Taking the Plunge into a Young Star" (January 6, 2017)
hubblesite.org/news_release/news/2017-02
The Hubble Space Telescope detected evidence of comets falling into star HD 172555, based on observations of:
(A) flickering star brightnesses.
(B) a young gas-giant planet.
(C) rapidly moving gaseous debris.
(D) ice crystal reflections.
(E) comet tail formation.

Correct answer: (C)

Student responses
Sections 30679, 30680
(A) : 7 students
(B) : 7 students
(C) : 13 students
(D) : 3 students
(E) : 3 students

Astronomy current events question: revised age of the moon

Astronomy 210L, spring semester 2017
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!)
Stuart Wolpert, "The Moon is Older than Scientists Thought, UCLA-led Research Team Reports" (January 11, 2017)
newsroom.ucla.edu/releases/the-moon-is-older-than-scientists-thought-ucla-led-research-team-reports
The age of the moon has been revised to be older than previously thought, based on analysis of moon samples brought to Earth by:
(A) Apollo mission astronauts in 1970.
(B) the Chinese moon rover Yutu.
(C) Google Project X.
(D) lunar impact meteorites.
(E) the aurora borealis.

Correct answer: (A)

Student responses
Sections 30679, 30680
(A) : 23 students
(B) : 3 students
(C) : 3 students
(D) : 4 students
(E) : 0 students

Astronomy current events question: extra-galactic origin of distant stars in Milky Way galaxy

Astronomy 210L, spring semester 2017
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!)
Christine Pulliam, "Farthest Stars in Milky Way Might Be Ripped from Another Galaxy" (January 11, 2017)
cfa.harvard.edu/news/2017-02
Our Milky Way galaxy's farthest known stars may have been ripped from the neighboring Sagittarius dwarf galaxy, based on matching the stars' __________ with computer simulations.
(A) positions and velocities.
(B) sizes and temperatures.
(C) ages.
(D) compositions.
(E) fusion rates.

Correct answer: (A)

Student responses
Sections 30679, 30680
(A) : 26 students
(B) : 4 students
(C) : 2 students
(D) : 1 student
(E) : 0 students

Online reading assignment: double-slit interference

Physics 205B, spring semester 2017
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 presentations on double-slit interference.


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 know the difference between maxima and minima."

"That the path length difference relation tells us where the maxima or minima will be."

"With the double-slit interference, the source phase differences don't matter, but that just their path differences do, we are wanting to know how much longer the wave from one source travels than the wave from the other source. I also understood that in a double-slit interference condition the constructive is maxima, and a condition that is destructive is minima."

"Double slit interference is two side-by-side in-phase sources. Phase differences don't matter with this and only the path matters. When calculating this we locate where these two sources interfere constructive (maxima) or destructively (minima)."

"A really small difference in distances can put waves in interference with each other; it is interesting how much of a difference it can be."

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.
"I am not understanding the flow chart for the constructive and destructive conditions. How am I able to tell which pathway I am to choose for the condition I am given?"

"How to figure out the difference between the minima and maxima for double-slit interference."

"Path length differences. I'm just not fully understanding on how to find it."

"I don't really understand what double-slit interference is."

Explain the difference between "maxima" and "minima" in double-slit interference.
"Constructive interference is maxima and minima is destructive interference."

"The difference between the two is that the maxima is when there is a constructive interference or when the path difference is a multiple of the wavelength. A minima happens when there is a destructive interference or when the path difference is either an odd number of half wavelengths."

"No idea."

"I'm trying to understand it."

"Maxima and minima is the minimum and maximum of wavelength?"

Match the double-slit parameter with its symbol. (Only correct responses shown.)
Distance between slits: d [77%]
Any positive or negative whole number: m [77%]
Distance from slits to a projection screen: L [41%]
Wavelength of light passing through both slits: λ [100%]
Difference in paths for light passing through both slits: d·sinθ [50%]
Position along screen, as measured from the centerline: y [46%]

Identify the characteristics of the sources, path difference, and interference type. (Only correct responses shown.)
Sources: in phase [95%]
Path difference: integer number of wavelengths [91%]
Interference: constructive [91%]

Identify the characteristics of the sources, path difference, and interference type. (Only correct responses shown.)
Sources: in phase [59%]
Path difference: odd number of half wavelengths [86%]
Interference: destructive [77%]

Identify the characteristics of the sources, path difference, and interference type. (Only correct responses shown.)
Sources: in phase [73%]
Path difference: integer number of wavelengths [82%]
Interference: constructive [68%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Can we discuss the difference between maxima and minima in double-slit interference?

"Do we call it maxima/minima only when we're talking about interfering waves?" (Well, yes, but this works for both interfering sound waves (loud/quiet regions) or interfering light waves (bright/dark regions).)

"Petition for more long weekends!"

"Did you ride any emus over the long weekend?" (No, but Mrs. P-dog and I went snowshoeing up in the mountains.)

20170222

Online reading assignment: runaway planets, jovian planets, and dwarf planets (oh my!) (SLO campus)

Astronomy 210, spring semester 2017
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 runaway planets (Venus and Mars), jovian planets (Jupiter, Saturn, Uranus and Neptune), and the dwarf planets (and the International Astronomy Union classification scheme).


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 found the greenhouse factors unique to each planet was particularly interesting and I was able to read and see how each planet was affected by its conditions and atmosphere."

"The 'frustrated volcanos' on Venus were interesting because The Simpsons GIF animation really made it make a lot of sense."

"Venus may have had a lot of water but due to the greenhouse affect the water turned into vapor and now the planet's greenhouse effect gets worse with time, and I find that fascinating because it proves the possible extreme result of Earth's global warming and human activity in the worsening of our greenhouse effect."

"That Venus and Mars are considered 'runaway' planets because of the fact that they have lost their greenhouse gas cycles...which kinda worries me because what if earth also starts to do the same?"

"That how much mass a planet has contributes to the amount of greenhouse gases it lets out into the atmosphere. Also, how the distance from the sun to the planet determines how much warming there will be from the greenhouse effect."

"The dwarf planets!!!! I had no clue there were other dwarf planets than pluto! Wicked. Haumea is the most interesting to me by far, it's interesting that they classify it "round enough" to be a dwarf planet."

"It is good to finally know why Pluto is no longer considered a planet. Before, I just accepted that fact without giving it too much thought."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I am confused how both Venus and Mars can have volcanos without plate tectonics."

"Why is Venus so much hotter than Mars since their masses aren't vastly different, and orbits aren't that significantly different?"

"The whole greenhouse things and how they relate to different planets, if you could please go into detail that would be great."

"Greenhouse effect factors are still pretty confusing for me. I've been trying to read up on it more, but I think I just need a simpler way of understanding it! The more I read about it, the more confused I get."

"Uranus--is the axis really that drastically tilted, and could you explain again the impact this has on making it cooler than Neptune?"

"I found Kuiper belt a bit confusing. What exactly is the belt and why are the objects, such as Pluto, located on that belt not considered planets."

"More about Pluto and why it's no longer a planet."

Identify the relative amounts of these characteristics for Venus, compared to Earth. (Only correct responses shown.)
Interior core heat, today: about the same as Earth [51%]
Geologic activity, today: less than Earth [64%]
Volcanic outgassing, up until now: about the same as Earth [43%]
Heat from the sun: more than Earth [84%]
Amount of atmosphere, today: more than Earth [65%]

Identify the relative amounts of these characteristics for Mars, compared to Earth. (Only correct responses shown.)
Interior core heat, today: less than Earth [81%]
Geologic activity, today: less than Earth [83%]
Volcanic outgassing, up until now: less than Earth [62%]
Heat from the sun: less than Earth [81%]
Amount of atmosphere, today: less than Earth [92%]

Which jovian planet has the coolest interior temperatures?
Jupiter (most massive).   **** [4]
Saturn (most prominent rings).   [0]
Uranus (least active weather patterns).   ******************** [20]
Neptune (farthest from the sun).   ********** [10]
(Unsure/guessing/lost/help!)   *** [3]

I believe Pluto should be a planet.
Strongly disagree.   * [1]
Disagree.   ***** [5]
Neutral.   ******************** [20]
Agree.   ******* [7]
Strongly Agree.   **** [4]

Briefly explain your answer to the previous question (whether Pluto should be a planet).
"Pluto is considered a dwarf planet, along with four others along the Kuiper belt. Pluto was once considered a planet. For the sake of argument, if Pluto was a planet, then the other four should be as well, as they are all on the Kuiper belt. But just because they are all on there doesn't mean they should all be planets."

"If Pluto no longer fulfils the requirements of planethood, then I have no problem with it not being a planet."

"Because it is itsy-bitsy, and scientists say so."

"It's not up to me if it is a planet or not."

"I'm fairly neutral on the topic. I feel if they outline a criteria for what defines a planet then they need to hold consistent with that criteria and no exceptions should be made. If Pluto is granted an exceptions then what is stopping people from defining some of the other dwarf planets as actual planets?"

"I believe if something has moons, it should be considered a planet."

"I grew up with Pluto being a planet, plus I liked Pluto the Dog from Disney movies."

"You can't give a present and take it back without being rude. Can't give it planethood and take it back without being rude either."

"Pluto is like the main character in My Big Fat Greek Wedding that couldn't sit with the cool crowd because her lunch wasn't in a brown paper bag.

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"What exactly is 'outgassing?'" (Gases spewed out into the atmosphere from volcanoes and vents, released from bubbles in molten rock under the crust. So basically, Earth is burping.)

"Ok, from what I have heard and from what is on NASA's website, NASA wants to 'colonize"' Mars. It is to my understanding that Mars is unable to be inhabited by anything because of its low mass and it's practically non-existent volcanic activity to create an atmosphere suitable to sustain life like Earth. So my question is, is it possible? (Yes, if we send people who don't mind staying indoors most of their time, in underground shelters.)

"Do you think Pluto should be a planet? Do you think that we all feel a little bit like Pluto sometimes?" (No, because, reasons. And yes, but that's life.)

"Do you like to go out and get your groove on in downtown SLO? If yes, what is one of your favorite bars to go to?" (I'm one of the DJs for swing dancing at the Madonna Inn on Monday nights.)

"How was your break?" (Mrs. P-dog and I had a snow day up in the mountains. It was awesome. How was your break?)

20170221

Online reading assignment: runaway planets, jovian planets, and dwarf planets (oh my!) (NC campus)

Astronomy 210, spring semester 2017
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 runaway planets (Venus and Mars), jovian planets (Jupiter, Saturn, Uranus and Neptune), and the dwarf planets (and the International Astronomy Union classification scheme).


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.
"That Venus's crust is so flexible it is unable to break into moving plates."

"The different weather on each of the planets is so unique and it would be interesting to see in person."

"The different atmospheres of the planets. It is really cool to hear how the atmospheres differ and why they are different."

"That low mass planets lose heat faster--I thought the small space would be able to retain heat easier."

"I think its interesting that Neptune is blue because the methane! I also think its cool that an astronaut could 'swim' through Saturn's rings. I also didn't know Mars was red because of rust!"

"Sunlight helps give the gas giants their bold colors. Well Jupiter, that's why it's so much brighter and colorful than Saturn."

"The categorization scheme on what defines a planet--I was wondering how you categorize a moon being a moon and a planet being a planet. And now there is a new classification called dwarf planets and that's what Pluto is now considered. I wondered about that since it is no longer considered a planet. That Pluto is no longer a planet and now I know why and I agree that it shouldn't be. As we gain new knowledge some old truths get ruled out with new data. That's what science is about."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I think all the information about the planets and comparing them to Earth. Like Venus and Mars compared to Earth. I'd like a little more of a basic breakdown of the comparisons."

"The planetary greenhouse effect factors: mass, distance, temperatures and all that--maybe a little more reading and practice will help; I'm just a little confused right now."

"The comparisons between Venus and Mars to Earth. I was mostly looking at the mass of the planets to gauge the differences."

"How Pluto isn't a planet."

Identify the relative amounts of these characteristics for Venus, compared to Earth. (Only correct responses shown.)
Interior core heat, today: about the same as Earth [20%]
Geologic activity, today: less than Earth [60%]
Volcanic outgassing, up until now: about the same as Earth [35%]
Heat from the sun: more than Earth [75%]
Amount of atmosphere, today: more than Earth [80%]

Identify the relative amounts of these characteristics for Mars, compared to Earth. (Only correct responses shown.)
Interior core heat, today: less than Earth [90%]
Geologic activity, today: less than Earth [80%]
Volcanic outgassing, up until now: less than Earth [75%]
Heat from the sun: less than Earth [85%]
Amount of atmosphere, today: less than Earth [95%]

Which jovian planet has the coolest interior temperatures?
Jupiter (most massive).   [0]
Saturn (most prominent rings).   [0]
Uranus (least active weather patterns).   *********** [11]
Neptune (farthest from the sun).   ******* [7]
(Unsure/guessing/lost/help!)   ** [2]

I believe Pluto should be a planet.
Strongly disagree.   * [1]
Disagree.   *** [3]
Neutral.   *********** [11]
Agree.   ** [2]
Strongly Agree.   *** [3]

Briefly explain your answer to the previous question (whether Pluto should be a planet).
"I believe that anything that consistently orbits around the sun should be considered a planet. Plus, it's my favorite planet. And I found that Earth is hit with asteroids and debris just as often as Pluto, therefor that is not enough of a reason to classify it as a non-planet (learningmind.com)."

"It used to be one so it should still be one."

"I don't really have an opinion. I mean, I kind of wish Pluto was still a planet. I mean, its kind of not fair to classify it as a planet and then take it away. But, I don't really have more of an opinion than that."

"Ohana means family! Family means no one gets left behind! jk :)"

"Pluto was a planet to me until it wasn't. It's awkward now that its not. I feel like he's lonely. I guess I feel neutral about it."

"Pluto shares orbital space with lots of other object out in the Kuiper belt, being very icy and super-small. Pluto does not dominate the neighborhood around its orbit."


Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"When will we get a chance to look at the telescopes the North County campus?" (When it stops raining long enough for the swamp around the telescope shelter to dry out.)

"I'm still a little confused as to why Uranus' interior would have been stirred more than Neptune's causing Uranus to cool off faster. The water bottle in the ice bath analogy didn't really make sense because, in one of the ice baths, the bottle wasn't rotating at all. Don't both Uranus and Neptune both rotate?" (Yes, they both rotate, so they should be both cool off at the same rate. However, Uranus' rotational axis is tilted over probably from a large impact event which would have dramatically shaken and stirred its interior for a brief time, so that would have cooled off its interior dramatically more than Neptune.)

"Do you think Pluto should be considered a planet?" (No, because, reasons.)

"The way you relate facts to things we can see in everyday life is so helpful! The gravy skin and tectonic plates... :D I will never forget that analogy!"

"Why are we funding space research versus researching more ways that we can help cut back on CO2 production and help preserve Earth?" (We use a lot of the same technology developed to observe and understand other planetary climates to observe and understand Earth's climate, which is a big first step to try to address global warming. Also, NASA's share of the U.S. budget is only 0.8% each year.)

"Since the jovian planets accumulated ice and helium/low density hydrogen to make them bigger, could they continue to grow through the present day?" (No, because all the dust and gas between planets has been cleared out, so barring pulling in any random asteroid or comet, the jovian planet sizes and masses are pretty much set.)
"I didn't quite understand why Pluto has a faster orbit around the sun than Neptune. It's confusing to me because Pluto's orbit is slightly larger than Neptune's, so that's where I'm stuck." (Pluto's period is slightly longer than Neptune's (248 years versus 165 years.))

20170220

Astronomy quiz question: August 2017 partial solar eclipse in San Luis Obispo, CA

Astronomy 210 Quiz 2, spring semester 2017
Cuesta College, San Luis Obispo, CA

A total solar eclipse will occur on August 21, 2017 for many observers in the United States[*]. During this event, observers San Luis Obispo, CA will only see a partial solar eclipse[**], because they will be located in:
(A) the moon's umbra.
(B) the moon's penumbra.
(C) the moon's negative shadow.
(D) Earth's umbra.
(E) Earth's penumbra.

[*] eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2017Aug21Tgoogle.html.
[**] timeanddate.com/eclipse/in/usa/san-luis-obispo?iso=20170821.

Correct answer: (B)

An observer in the moon's penumbra will see a partial solar eclipse, while an observer in the moon's umbra will see a total solar eclipse. (The "negative shadow" refers to the antumbra of the moon.)

Section 30674
Exam code: quiz02n1hT
(A) : 2 students
(B) : 17 students
(C) : 0 students
(D) : 2 students
(E) : 2 students

Success level: 76% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38

Section 30676
Exam code: quiz02sNoO
(A) : 3 students
(B) : 28 students
(C) : 1 student
(D) : 3 students
(E) : 7 students

Success level: 69% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64

Astronomy quiz question: planet(s) visible at sunset?

Astronomy 210 Quiz 2, spring semester 2017
Cuesta College, San Luis Obispo, CA

Tthe locations of Venus, Earth and Mars are shown in the diagram below (not to scale, and orbits have been simplified as circles instead of ellipses).


Which planet(s) will be visible at sunrise?
(A) Venus.
(B) Mars.
(C) (Both of the above choices.)
(D) (Neither of the above choices.)

Correct answer (highlight to unhide): (B)

If a line is drawn from Earth to the sun, the observer at sunset (6 PM) is located perpendicular to that line. Since Venus is below that horizon line, it would not be visible at that time; while Mars is above that horizon line, it would be visible high over the east horizon at that time.


Section 30676
Exam code: quiz02sNoO
(A) : 11 students
(B) : 24 students
(C) : 2 students
(D) : 5 students

Success level: 60% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.91

Astronomy quiz question: planet(s) visible at sunrise?

Astronomy 210 Quiz 2, spring semester 2017
Cuesta College, San Luis Obispo, CA

Tthe locations of Venus, Earth and Mars are shown in the diagram below (not to scale, and orbits have been simplified as circles instead of ellipses).


Which planet(s) will be visible at sunrise?
(A) Venus.
(B) Mars.
(C) (Both of the above choices.)
(D) (Neither of the above choices.)

Correct answer (highlight to unhide): (A)

If a line is drawn from Earth to the sun, the observer at sunrise (6 AM) is located perpendicular to that line. Since Mars is below that horizon line, it would not be visible at that time; while Venus is above that horizon line, it would be visible low over the east horizon at that time.


Section 30674
Exam code: quiz02n1hT
(A) : 19 students
(B) : 0 students
(C) : 2 students
(D) : 2 students

Success level: 84% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.17

20170217

Astronomy quiz archive: eclipses/history of astronomy

Astronomy 210 Quiz 2, spring semester 2017
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz02n1hT

Section 30674
0- 8.0 :  
8.5-16.0 :  
16.5-24.0 :   ****** [low = 20.0]
24.5-32.0 :   ********* [mean = 29.1 +/- 5.6]
32.5-40.0 :   ******** [high = 40.0]


Section 30676, version 1
Exam code: quiz02sNoO

Section 30676
0- 8.0 :   * [low = 8.0]
8.5-16.0 :   *******
16.5-24.0 :   ***********
24.5-32.0 :   ********* [mean = 24.5 +/- 7.8]
32.5-40.0 :   ********* [high = 40.0]