20190830

Astronomy quiz question: third quarter moon setting

Astronomy 210 Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

What time is it when the third quarter moon is setting?
(A) 12:00 PM (noon).
(B) 3:00 PM (afternoon).
(C) 6:00 PM (sunset).
(D) 9:00 PM (evening).
(E) 12:00 AM (midnight).
(F) 3:00 AM (wee hours).
(G) 6:00 AM (sunrise).
(H) 9:00 AM (morning).

Correct answer (highlight to unhide): (A)

The third quarter moon is highest overhead at 6:00 AM. In a simple model of lunar phases, the moon will take 12 hours from rising to setting, and so will take six hours from being highest overhead (at 6:00 AM) to subsequently set at 12:00 PM.

Section 70158
Exam code: quiz01SLYc
(A) : 17 students
(B) : 0 students
(C) : 9 students
(D) : 1 student
(E) : 5 students
(F) : 4 students
(G) : 3 students
(H) : 1 student
(No responses: 1 student)

Success level: 41% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73

Astronomy quiz question: rise/set positions and paths of the sun

Astronomy 210 Quiz 6, fall semester 2016
Cuesta College, San Luis Obispo, CA

An observer in San Luis Obispo, CA watches the sun in June. As soon as __________ later, the sun will rise on the horizon due east.
(A) 10 hours.
(B) 12 hours.
(C) 14 hours.
(D) One month.
(E) Three months.
(F) Six months.

Correct answer (highlight to unhide): (E)

Students completed this diagram of the paths for the sun for San Luis Obispo, CA on an in-class activity ("lecture-tutorial"). However, this diagram was not provided on the quiz.


In June, the sun will rise on the horizon between northeast and east, and takes 14 hours to set on the horizon between west and northwest. The sun will rise on the horizon due east during March or September. So the soonest that the sun will rise on the horizon due east after June would be September, three months later.

Section 70158
Exam code: quiz01SLYc
(A) : 13 students
(B) : 25 students
(C) : 4 studenst
(D) : 0 students
(E) : 10 students
(F) : 2 students

Success level: 26% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64

Astronomy current events question: Chesapeake Bay asteroid impact crater

Astronomy 210L, fall semester 2019
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!)
Karen Valentine, "ASU Researchers Study Largest Impact Crater in the US, Buried for 35 Million Years" (August 8, 2019)
asunow.asu.edu/20190808-asu-researchers-study-largest-impact-crater-us-buried-35-million-years
Analysis of __________ from drilling samples provide evidence of the Chesapeake Bay asteroid impact 35 million years ago.
(A) water salinity.
(B) trapped gases.
(C) shocked crystals.
(D) extraterrestrial minerals.
(E) prehistoric mammal fossils.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 2 students
(B) : 2 students
(C) : 31 students
(D) : 3 students
(E) : 1 student

Astronomy current events question: black hole and neutron star merger

Astronomy 210L, fall semester 2019
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!)
Michael Greshko, "Astronomers Probably Just Saw a Black Hole Swallow a Dead Star" (August 16, 2019)
nationalgeographic.com/science/2019/08/astronomers-probably-just-saw-black-hole-swallow-neutron-star/
Gravitational waves detected from the S190814bv event provide evidence that __________ 900 million years ago.
(A) a sunquake erupted.
(B) a smaller big bang occurred.
(C) a supernova exploded near Earth.
(D) a black hole and neutron star merged.
(E) the Milky Way swallowed a dwarf galaxy.

Correct answer: (D)

Student responses
Sections 70178, 70186
(A) : 0 students
(B) : 0 students
(C) : 2 students
(D) : 37 students
(E) : 0 students

Astronomy current events question: exoplanet naming

Astronomy 210L, fall semester 2019
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!)
Derrick Pitts, "You Can Name An Exoplanet!" (August 8, 2019)
fi.edu/blog/you-could-name-an-exoplanet
The International Astronomical Union is allowing each country to name an exoplanet and its host star __________ that country.
(A) discovered by.
(B) to be colonized by.
(C) visible in the sky from.
(D) with climates matching.
(E) after explorers born in.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 6 students
(B) : 0 students
(C) : 29 students
(D) : 3 students
(E) : 1 student

20190828

Online reading assignment: eclipses, history of astronomy (SLO campus)

Astronomy 210, fall semester 2019
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 eclipses, and an preliminary overview of the history of astronomy.


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 was interested when I started to find more out about astrology. I wasn't sure what it was or what is had to do with. I was surprised when I found out that a zodiac sign is what constellation the sun lined up with on your birthday. It was interesting to find out that I'm not the zodiac sign I was. This has to do with precession."

"That there are different types of eclipses! I thought there was only one! The differences in eclipses is what interest me the most and am awaiting the class discussion behind these things."

"A lunar eclipse happens when the moon is in the umbra of Earth's shadow. I like imagining Earth blocking the sunlight to the moon. I found it interesting that the moon entering the umbra can take up to an hour and another hour for the moon to be totally eclipsed. I have always wanted to see a total lunar eclipse, so understanding how it works and the process it takes to totality is intriguing."

"That it is always full moon during a lunar eclipse, and that it is always new moon during a solar eclipse. Also interesting to me was that the lunar orbit path around Earth is like a spinning coin or spinning plate that's about to fall flat (can't think of another way to describe it)...And that is how the moon gets light from the sun even when it is behind Earth. And when that orbit path aligns just right we get eclipses...very interesting!"

"That lunar eclipses always happen during a full moon. But for every full moon there isn't going to be a lunar eclipse."

"I always wondered why lunar eclipses have a copper-red color--now I know the glow is created by Earth's simultaneous sunrises and sunsets, which illuminate the moon during totality. I watched a lunar eclipse within this past year, but had no knowledge of how eclipses worked."

"I had never heard of annular eclipses, and they seem crazy to see. I’m surprised they are not more commonly talked about."

"I actually did not realize that we has occurrences like annular solar eclipses. From my lifetime, I can only remember only ever hearing about and seeing total solar eclipses. I looked up images, and the annular solar eclipses are amazing!"

"Personally, I never really paid any attention to solar eclipses or lunar eclipses, but reading about them and all their different positions/ components was rather interesting and made me look forward to possibly seeing one someday."

"We don't see an eclipse every full moon because the moon is either tilted too high or too low. The bottom or top part of the moon is how you can tell if there is an eclipse or not."

"I love learning about the astronomers of history and how they made discoveries about the night sky. Without them, we would be sitting in class learning about how we're the center of the universe!"

"I have to say that the idea of a paradigm of a geocentric universe is very interesting. It makes sense to an extent--people just want to agree with what further strengthens their preexisting beliefs, but it's also strange that they were not open to new ideas and understandings. Nowadays, I feel like most of us are open to new ideas and proposals and just sticking with old-school beliefs or styles (in regards to anything) seems counterproductive. I understand why they fell victim to these paradigms, it's just interesting to see how the scientific method and other things of the same sort have allowed for modernization in beliefs."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"The eclipse thing was also confusing to me for quite a while. I sat and looked over the book and presentation multiple times to try and figure out which phases did what and when it didn't matter or if it did."

"How to tell the difference between solar and lunar eclipses."

"It took me a while to fully comprehend the idea of lunar and solar eclipses. I couldn't figure out how they worked or why. I still don't truly understand the true reason why the moon goes in front of the sun or why Earth ends up in front of the moon, but for the most part I get it."

"I still can't quite grasp the idea of how the sun, moon, and Earth line up to create eclipses, and why it doesn’t happen more often."

"The umbra and penumbra of the moon is difficult to understand when thinking about how the shadows effect the visibility of the sun. I have a hard time imagining how the umbra covers the earth surface fully while the penumbra would give you a partial eclipse."

"Do the phases of the moon look different from different places on Earth? Why isn't there an eclipse at every new/full moon?"

"I'm still a bit lost in understanding why eclipses do or do not happen during every new or full moon. I get that it involves the orbit of the moon being too high or too low, but I'm having trouble distinguishing what the 'perfect' angle is for an eclipse to occur."

"Remembering names and dates isn't exactly my strong suit, and trying to distinguish and remember each of the seven astronomers and what they individually did, without confusing them together, is somewhat difficult for me."

"Why were ancient astronomers so dead set on following the first principles and never questioned the accuracy of them?"

"I found it challenging to remember all of the categorization of all of the different astronomers and what they all mean. I think it will just take me more time and practice to match each category to astronomer."

"Nothing this week was confusing in any way."

A friend of yours has a birthday on March 30. According to your starwheel, the sun would have been located in front of which zodiac sign on that date? (Ignore daylight saving time.)
Aries.  **** [4]
Taurus.  *[1]
Gemini.  [0]
Cancer.  [0]
Leo.  [0]
Virgo.  **** [4]
Libra.  [0]
Scorpio.  [0]
Sagittarius.  [0]
Capricorn.  [0]
Aquarius.  ** [2]
Pisces.  *********************** [23]
(Unsure/guessing/lost/help!)  ****** [6]

I believe astrology is able to make accurate predictions about my future. (This is a follow-up question.)
Strongly disagree.  ****** [6]
Disagree.  ****************** [18]
Neutral.  ******* [7]
Agree.  ******** [8]
Strongly agree.  * [1]

Briefly discuss what you know now (that you didn't know before) that may (or may not have) affected your earlier opinion regarding your belief/disbelief in astrology. (This is a follow-up question.)
"I feel the same way. Before I had said that Astrology was a form of pseudoscience, that's why I didn't believe it could possibly make accurate predictions about my future."

"Astrology being off by a month. Didn't change my opinion much."

"I had no idea that astrology was off by a whole month due to precession, and I actually find it pretty funny. This further affirms my belief that astrology is pseudoscience."

"No new information was provided that changed my perspective on astrology. I'm not saying its not a thing... I'm just saying it can't be used to predict/determine human behavior or personal information."

"I feel the same about astrology. Its fun to read sometimes but I don't think it actually makes accurate predictions about the future."

"I learned that you can go back in time within a database and find out exactly what the night sky looked like on a particular night 3,000 years ago. This fact reiterates what I had previously stated in my disbelief of astrology. I still think astrology can make somewhat accurate predictions about the future night sky, but it cannot make accurate predictions about my future in particular. My future life is solely dependent upon my choices."

"I'm honestly just mildy annoyed that I am an Ares and not a Taurus. And every connection that I've seen with myself and the 'Taurus' identity confuses me greatly."

"Nothing has affected my beliefs in astrology up until now. I've thought it was bogus ever since I started a degree in astrophysics back at UC Riverside two years ago."

"The planets are not in perfect orbits, and are not a part of a mystical heavenly clock, such as what the Greeks believed. And still don't believe in it."

"My opinion is still the same. I think western astrology is bogus. Whereas India astrology, aka Jyotish, from what I have heard (anecdotal I guess), can make very accurate predictions (this is what some of my Indian friends have told me). I know that, for example, the shifting of the north star is something that IS accounted for in their calculations. Regardless, I am still neutral about astrology."

"The starwheel affected my belief in astrology because it gave me a different zodiac sign. I was under the belief that I was a Taurus but the star wheel says that I am an Aries."

"I never knew much about the science behind astrology all I knew is that I was a Pisces and anything I looked up about my sign aligned a lot in some ways with how I view myself."

"I didn't know that your sun sign is the zodiac constellation the sun is in on your birthday honestly. It didn't really influence my neutral attitude towards astrology though."

"I now know a lot more about the specific type of moon phases and eclipse types, which I didn't know much about before taking this class. Knowing more about astrology solidifies my belief in it."

"I know astrology is not accurate but I still am entertained by it and definitely read my horoscope on the regular. Also, I am kinda mad about the fact that I am actually a Cancer and not a Leo (July 23rd)."

"I still have the same opinion because what I learn in class of our zodiac signs and what I have read still makes me believe that astrology can predict the future but it can make mistakes."

"My opinion remains unchanged, people can believe what they want as long as their beliefs do not impede others ideals."

"I think that there are some things that can be predicted using science (such as when certain celestial bodies will be in certain places) however this has little to do with what we commonly refer to as 'astrology.'"

"With the sun signs being a month off from common astrology signs, predictions will overlap and be different depending on who is making them."

"I always believed in astrology so I am biased."

"I didn't know how zodiac signs worked previous to this class. After learning that zodiacs came from constellations I was really intruigued on how that all worked, but I still don't think it has anything to do with my future or any of that."

"Everything I’ve learned so far has only further strengthened my belief in astrological phenomena :-)"

"I never knew that your sun-sign changes do too the change of axis. Everyone has a completely different zodiac sign then they previously thought!"

"I don't think the position of the stars while you were born has a huge impact on your personality traits."

"Since astrology seems to be so popular right now, it's almost funny to think that people use their sun signs as justification for their behavior, yet in reality they are an entirely different sign but they don't know it yet."

"I learned a bit about how the sun and stars move throughout the year with the zodiac constellations and as I do believe the zodiac signs effect some monthly changes in the universe. I still don't believe in astrology, because I don't believe the alignment of the sun and stars on our birth months actually effects who we are as people."

"Well now I know that there are lunar and solar eclipses and the annular."

"I now know that everyone's original zodiac sign is a month different than what it really is. It is interesting to see that this has been different for many years and people rarely shine light upon the subject."

"Nothing will change my opinion on the matter."

"I believe I still feel the same. Believing there is some truth but it is usually taken overboard."

"I did not know that the zodiac signs were assigned based on when the sun went through the star paths during certain months. I also didn't know that they change either. I thought they were just given random months just because, but now I know otherwise."

"Again, astrology can tell me no more than where the planet will be in its orbit in six months. It cannot predict that I will find the love of my life this week and then dump him two months later because he bought be the wrong flowers."

"I don't believe horoscopes because according to the starwheel on my birthday, my true zodiac is between Sagittarius and Libra. There's a disparity between 'wikipedia' zodiacs and true zodiacs."

"I feel like maybe it has some type of effect, like maybe it'll explain like good or bad luck (?) but ultimately it goes come down to you as a person and the choices you make."

Match the phase of the moon during these eclipse types. (Only correct responses shown.)
Total solar eclipse: new moon [80%]
Partial solar eclipse: new moon [60%]
Annular solar eclipse: new moon [53%]
Total lunar eclipse: full moon [88%]
Partial lunar eclipse: full moon [58%]

Place these astronomers in chronological order of their historical contribution to astronomy. (Only correct responses shown.)
Aristotle [83%]
Ptolemy [68%]
Copernicus [75%]
Tycho [70%]
Kepler [70%]
Galileo [53%]
Newton [83%]

Match these terms with their descriptions. (Only correct responses shown.)
Ideas accepted as truth without further examination: first principles [80%]
Predictions that could be tested by observations: hypotheses [95%]
Universal statements of cause and effect: rational laws [75%]
Describe phenomena without explaining why it occurs: empirical laws [60%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I never study astronomy before, and I was always curious about how does the universe work and how it was created. Therefore, what I learn when I read the chapters and during lectures is very fascinating."

"Could you maybe talk about the moon phases relating to the eclipse types?"

"I would like some demonstrations/further explanation on the solar and lunar eclipses."

"I couldn't find anything in the reading on how the phase of the moon is related to solar and lunar eclipses."

"I am amazed at the theories that some of these ancient astronomers had, and some that I had never even heard of before."

"Terms and descriptions for first principles, empirical laws, hypotheses, and rational laws wasn't very clear to me. Could you elaborate in class?"

Online reading assignment: free fall, vector components

Physics 205A, fall semester 2019
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 free fall and vector components.


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.
"How to find the right variables for a problem by analyzing which parts of the information are given and which are not. I also understand how to determine which of the kinematic equations to use by determining which of the five variables needs to be found and how to rule out a variable that doesn't need to be found."

"Things can be thrown upwards (start with positive velocity), thrown downwards (start with negative velocity), or dropped (start with zero velocity)."

"During free fall, air resistance is neglected and the acceleration is nearly constant. Because acceleration is constant, we can use kinematic equations. Using a right triangle we are able to define sinθ cosθ and tanθ which helps us solve problems that involve angles. Scalars are numbers with magnitude such as time and volume while vectors are quantities with magnitude and direction such as displacement and velocity."

"I understand that an object can have a different vertical distance traveled than magnitude of vertical displacement. This is dependent on if the object is thrown straight in the air and then free falls, dropped into free fall, or thrown downward. I believe that the vertical displacement is equal to the distance if the object is dropped or thrown down, but the distance traveled is GREATER than the displacement if the object is thrown up."

"The fact that the only force acting on a ball falling down is gravity which has a constant acceleration is consistent with my understanding of physics. I also understand that vectors are determined by the x and y components in a triangle bringing us back to trigonometry.

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 was confused about how an object thrown or shot upwards can reach the same speed when it comes back down to its initial starting point as when it is thrown or shot downwards from its starting point."

"I found the homework problems a little bit confusing just because we haven't gone over many of those sorts of problems together. It would be very helpful to go over one of those specific problems in lecture."

"Trigonometry, but just a refresher would be useful.

Explain what assumptions are made about the amount of drag (air resistance) on an object said to be in free fall.
"We assume that drag forces are negligible."

"Air resistance is ignored."

A boy steps off of a ledge (with no initial vertical velocity) and splashes into the water below.

Choose up to be the +y direction. The initial vertical velocity v0y has a __________ value.
negative.   *********** [11]
zero.   ********************************* [33]
positive.   *** [3]
(Unsure/guessing/lost/help!)   ** [2]
For the boy, the vertical distance traveled is __________ the magnitude of the vertical displacement.
less than.   *** [3]
equal to.   ************************************ [36]
greater than.   ******** [8]
(Unsure/guessing/lost/help!)   ** [2]

A ball is thrown and released downwards from the top of a building, and hits the ground below.

Choose up to be the +y direction. The initial vertical velocity v0y has a __________ value.
negative.   ************************* [25]
zero.   ********** [10]
positive.   ********* [9]
(Unsure/guessing/lost/help!)   ***** [5]
For the ball, the vertical distance traveled is __________ the magnitude of the vertical displacement.
less than.   ***** [5]
equal to.   **************************** [28]
greater than.   ****************** [13]
(Unsure/guessing/lost/help!)   *** [3]

A hat is thrown and released upwards into the air and lands on the grass below.

Choose up to be the +y direction. The initial vertical velocity v0y has a __________ value.
negative.   **** [4]
zero.   ****** [6]
positive.   *********************************** [35]
(Unsure/guessing/lost/help!)   **** [4]
For the hat, the vertical distance traveled is __________ the magnitude of the vertical displacement.
less than.   ***** [5]
equal to.   *** [3]
greater than.   ************************************** [38]
(Unsure/guessing/lost/help!)   *** [3]

Mark the level of your exposure to trigonometry (triangles, unit circles, inverse functions, Pythagorean theorem):
None at all.   * [1]
Slight.   *** [3]
Some.   ********** [10]
A fair amount.   ************************ [24]
A lot.   *********** [11]

Indicate the following trigonometric relations between angle θ, the opposite leg o, the adjacent leg a, and hypotenuse h for a right triangle. (Assume that the angle θ is in the first quadrant: 0° ≤ θ ≤ 90°.)
(Only correct responses shown.)
sin θ: (o/h) [92%]
cos θ: (a/h) [88%]
tan θ: (o/a) [88%]
hypotenuse h length: √(o2 + a2) [94%]

Describe what mnemonic device (if any) you use to memorize the right-triangle trigonometric relationships.
"Soh-cah-toa."

"Don't recall one."

"I've never heard one."

"I don't really use one."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"This is pretty cool. We are now moving into free fall which might start to make some things confusing and interesting when combining it with our horizontal motion knowledge."

"For the free fall examples above, would ground level be 0 or from when the ball left their hand?" (The convention used here is that we will always start at y = 0 at t = 0.)

"For all of the questions in this assignment, all of the initial velocities are zero? Because everything starts from not moving and is then thrown?" (If you throw a ball, it won't be in free fall (subject only to the force of gravity) until you let it go--so we can only start time t = 0 from the moment it was released with an initial velocity, as it leaves your hand.)

"Is there ever a setting where the free fall rules for falling objects don't apply?" (If air resistance (drag) is significant, then we can't say that acceleration is a constant value of 9.80 m/s2 downwards.)

"In terms of this class are we to automatically assume drag/air resistance doesn't matter or will it be noted?" (On the quizzes and midterms, it will always be stated whether or not air resistance is negligible.)

"The last time I used SOH CAH TOA was 10th grade, so it's a little fuzzy."

"Will we only be using trigonometry to solve problems? I like calculus but I get lost when it comes to applying it to physics for some reason." (We'll use trigonometry to break down diagonal vectors such that we can analyze horizontal and vertical motion separately for projectile motion.)

"Nothing to ask here. Looking forward to the lecture!"

20190827

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

Astronomy 210 Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz01SLYc

Section 70158
0- 8.0 :   * [low = 6.0]
8.5-16.0 :   ****************
16.5-24.0 :   ********** [mean = 21.6 +/- 8.6]
24.5-32.0 :   *************
32.5-40.0 :   **** [high = 40.0]


Section 70160, version 1
Exam code: quiz01nGh7

Section 70160
0- 8.0 :   *** [low = 8.0]
8.5-16.0 :   *******
16.5-24.0 :   ******* [mean = 19.0 +/- 7.6]
24.5-32.0 :   ***
32.5-40.0 :   * [high = 36.0]

Online reading assignment: eclipses, history of astronomy (NC campus)

Astronomy 210, fall semester 2019
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 eclipses, and an preliminary overview of the history of astronomy.


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.
"Precession. I had no idea that after thousands of years, our zodiac sign changes because of precession. It was engaging to learn about these changes because of the sky shifts. I was amazed at how Polaris wasn't a north star before."

"Eclipses are really cool and I've always wanted to know what has to occur in order for them to naturally happen."

"The differences between solar and lunar eclipses was interesting. The differences make more sense after reading about it on the presentation."

"I found both the solar and lunar eclipses interesting. The textbook does a well job in explaining what each of them is and how they can be predicted. I also wasn’t aware that there were more than two types of eclipses."

"I didn't know that there were specific eclipses such as partial or annular. I thought there was only total eclipses. I also found interesting how they tell you to look at a solar eclipse safely, though it makes sense so you don't harm your eyes."

"Retrograde motion. It took me a little bit too understand the concept, but blew me away when I actually figured it out."

"Finding out who were some of the big names is astronomy was interesting especially because for those that I knew about I had forgotten what they 'did.'"

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Learning about the moon's phases was confusing for me. Especially the 'all the moon questions' diagrams. I didn't know how to determine the overhead time until I positioned the moon in its orbit. This was because it was difficult to have the images of all the phases memorized."

"Something that I found confusing was the timing of an eclipse. It looks similar but just the time of the motions of earth inside the moon."

"I don't know the difference between a lunar and a solar eclipse."

"Overall everything was straightforward, I am slightly confused on how to identify each type of eclipse. Like I know the different types there are, I just don't know how to fully distinguish them from each other. Also, are we supposed to memorize all of the astronomers and what they did?"

"The retrograde motion of Mars. I am confused on why it seems to slow down and even come to a stop. I am confused on what causes this and is it just for Mars."

"Skimmed the reading but I got them mixed up and review would be nice. "

"Nothing really seemed too confusing, just interesting. I would like to go over the moon phases during an eclipse and the different kinds of astronomers."

A friend of yours has a birthday on March 30. According to your starwheel, the sun would have been located in front of which zodiac sign on that date? (Ignore daylight saving time.)
Aries.  * [1]
Taurus.  [0]
Gemini.  [0]
Cancer.  [0]
Leo.  [0]
Virgo.  * [1]
Libra.  [0]
Scorpio.  [0]
Sagittarius.  [0]
Capricorn.  [0]
Aquarius.  ** [2]
Pisces.  *************** [15]
(Unsure/guessing/lost/help!)  [0]

I believe astrology is able to make accurate predictions about my future. (This is a follow-up question.)
Strongly disagree.  ** [2]
Disagree.  **** [4]
Neutral.  ******** [8]
Agree.  **** [4]
Strongly agree.  * [1]

Briefly discuss what you know now (that you didn't know before) that may (or may not have) affected your earlier opinion regarding your belief/disbelief in astrology. (This is a follow-up question.)
"I remained neutral again, I still don't really understand how astrology would be able to predict my future, but I'm genuinely curious as to someone can do that."

"I now know that my astrological sign has changed since the ancient times and now I'm not so sure what sign I truly am."

"Nothing has changed. Astrology is pure fabrication."

"I honestly don't disagree with astrology nor do I believe in it, I did however learned that throughout time the constellations move as Earth rotates and that they don't always line up with their zodiac signs (if that makes any sense)."

"I still feel as though it holds some power as I shared before because I went according to my mood not from listening to my zodiac as apparently when I did it was all wrong. But it did make me doubt myself a little so now maybe my belief isn't so strong."

"I didn't know much about eclipses. All I knew before was the moon going in front of the sun and big shade occurring on a certain part of the planet. Yet now I know the more elements they have such as the umbra and penumbra. Which made me believe that there's more out there than I thought there was."

"My answer is still the same from the other reading assignment."

"I went through a brief phases where I'd use a few horoscope/prediction apps and sites to track if my day was going to go fine or not. Almost every prediction was exactly the same between references and the predictions themselves were almost entirely accurate for daily, weekly and monthly."

"My belief that astrology 'controls my life' is still neutral--however it was really fun pissing off my friends this weekend showing and proving to them that they were wrong about their zodiacs."

"Precession still blows me away about how much it affects, and the fact that astrologists still base their 'science' off of star charts from thousands of years ago makes me believe it's completely fake."

"What I know now is that the zodiac signs in astrology can have a meaning to you. Each sign has their different meanings and each person has a sign depending on their birthday."

"Same thing as before I just haven't had any impact."

Match the phase of the moon during these eclipse types. (Only correct responses shown.)
Total solar eclipse: new moon [84%]
Partial solar eclipse: new moon [53%]
Annular solar eclipse: new moon [42%]
Total lunar eclipse: full moon [89%]
Partial lunar eclipse: full moon [63%]

Place these astronomers in chronological order of their historical contribution to astronomy. (Only correct responses shown.)
Aristotle [79%]
Ptolemy [68%]
Copernicus [74%]
Tycho [47%]
Kepler [53%]
Galileo [42%]
Newton [58%]

Match these terms with their descriptions. (Only correct responses shown.)
Ideas accepted as truth without further examination: first principles [79%]
Predictions that could be tested by observations: hypotheses [63%]
Universal statements of cause and effect: rational laws [63%]
Describe phenomena without explaining why it occurs: empirical laws [47%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Could you please go over eclipses, it was very confusing for me to understand."

"Will we be shown visuals of the different types of eclipses during class?" (Yes.)

"It would be very helpful to know the answers to the the reading assignment after submitting it." (At the top of every reading assignment, there is a link so you can go over the answers to the previous reading assignment.)

"How did astronomers knew where and what was in space with very little technology?" (That is the history of astronomy, as it progressed from non-scientific thinking to the first science.)

"Will any of this be on the quiz we have tomorrow? If not will there be a quiz based on this information?" ((1) No, not on Quiz 1. (2) Yes, this new material (eclipses, history of astronomy, planetary motion) will be on Quiz 2.)

20190826

Physics quiz question: Swatch Internet Time beats

Physics 205A Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

Swatch Internet Time was proposed in 1988, where 1 day is divided into 1,000 "beats."[*] A day is defined to be 24 hours, an hour is defined to be 60 minutes, and a minute is defined to be 60 seconds. The duration of 1 beat is:
(A) 3.6 s.
(B) 86.4 s.
(C) 1.5×105 s.
(D) 8.64×107 s.

[*] swatch.com/en_us/internet-time#main.

Correct answer (highlight to unhide): (B)

The duration of a beat in seconds can be determined by setting up conversion factors such that unwanted units cancel (beats, days, hours, minutes) while desired units remain (seconds):

1 beat = (1 beat)·((1 d)/(1,000 beats))·((24 h)/(1 d))·((60 min)/(1 h))·((60 s)/(1 min)),

1 beat = (1 beat)·((1 d)/(1,000 beats))·((24 h)/(1 d))·((60 min)/(1 h))·((60 s)/(1 min)/),

1 beat = 86.4 seconds.

(Note that all of the factors in this calculation are exact definitions or conversion factors.)

(Response (A) is ((1/1000)·60·60; response (C) is (1000)·(1/24)·60·60; response (D) is (1000)·24·60·60.)

Sections 70854, 70855
Exam code: quiz01B34t
(A) : 3 students
(B) : 46 students
(C) : 4 students
(D) : 1 student

Success level: 84%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.42

Physics quiz question: computer chip nanoacreage

Physics 205A Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

A "nanoacre" is defined to be the area of a square 0.0792 inches by 0.0792 inches.[*] A VLSI (Very Large Scale Integration) computer chip has an area of 520 mm2.[**] A meter is defined to be 1,000 mm, and an inch is exactly equal to 25.4 mm. This computer chip has an area of:
(A) 4.05 nanoacres.
(B) 1.3×102 nanoacres.
(C) 2.6×102 nanoacres.
(D) 2.1×103 nanoacres.

[*] wki.pe/List_of_humorous_units_of_measurement#Nanoacre.
[**] johnloomis.org/ece531/notes/intro/intro.html.

Correct answer (highlight to unhide): (B)

The area of the computer chip in nanoacres can be determined from converting the units from the given value of square inches, by setting up conversion factors such that unwanted units cancel (in2, mm2) while desired units remain (nanoacres):

520 mm2 = 520 mm2·((1 in)/(25.4 mm))·((1 in)/(25.4 mm))·((1 nanoacre)/((0.0792 in)·(0.0792 in))),

520 mm2 = 520 mm2·((1 in)/(25.4 mm))·((1 in)/(25.4 mm))·((1 nanoacre)/((0.0792 in)·(0.0792 in))),

520 mm2 = 128.4947983629 nanoacres,

or to two significant figures, the computer chip area is 1.3×102 nanoacres.

(Response (A) is ((0.0792)·(25.4))2; response (C) is (520)/((0.0792)·(25.4)); response (D) is (520)·((0.0792)·(25.4))2).)

Sections 70854, 70855
Exam code: quiz01B34t
(A) : 4 students
(B) : 35 students
(C) : 8 students
(D) : 8 students

Success level: 64%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.58

Physics quiz question: mass diffusivity

Physics 205A Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

The Sherwood number SN is a dimensionless number that measures mass transfer and diffusion[*]:

SN = h/(D·L).

The convective coefficient h is measured in units of m·s–1, and the characteristic length L is measured in m. The units for mass diffusivity D are:
(A) s–1.
(B) s.
(C) m–2·s.
(D) m2·s–1.

[*] wki.pe/Sherwood_number.

Correct answer (highlight to unhide): (D)

Starting with the expression for the Sherwood number SN:

SN = h/(D/L),

the dynamic pressure D can be expressed as:

D = h·L/SN.

Then replacing the quantities in the equation with their m and s units, the units of D are:

D = m·s–1·m/(1)),

D = m2·s–1·m.

Sections 70854, 70855
Exam code: quiz01B34t
(A) : 13 students
(B) : 4 students
(C) : 2 students
(D) : 36 students

Success level: 65%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.44

Physics quiz question: dynamic pressure

Physics 205A Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

The drag force Fdrag (measured in units of kg·m·s–2) experienced by an object moving through a fluid is given by[*]:

Fdrag = q·As·CD.

The surface area As is measured in units of m2, and the drag coefficient CD is a dimensionless quantity. The units for the dynamic pressure q are:
(A) kg–1·m·s2.
(B) kg–1·m3·s2.
(C) kg·m–1·s–2.
(D) kg·m–3·s–2.

[*] wki.pe/Parasitic_drag#Description.

Correct answer (highlight to unhide): (C)

Starting with the expression for the drag force Fdrag:

Fdrag = q·As·CD,

the dynamic pressure q can be expressed as:

q = Fdrag/(As·CD).

Then replacing the quantities in the equation with their kg, m and s units, the units of q are:

q = kg·m·s–2/((m2)·(1)),

q = kg·m·s–2·m–2,

q = kg·m–1s–2.

Sections 70854, 70855
Exam code: quiz01B34t
(A) : 2 students
(B) : 2 students
(C) : 49 students
(D) : 2 students

Success level: 89%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.25

Physics quiz archive: metric system, significant figures, unit conversions, dimensional analysis

Physics 205A Quiz 1, fall semester 2019
Cuesta College, San Luis Obispo, CA
Sections 70854, 70855
Exam code: quiz01B34t



Sections 70854, 70855 results
0- 6 :   * [low = 6]
7-12 :   ****
13-18 :   *************
19-24 :   *********************** [mean = 21.4 +/- 5.7]
25-30 :   ************** [high = 30]

Online reading assignment: constant acceleration equations of motion

Physics 205A, fall semester 2019
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 reviewing a flipped class presentation on (constant acceleration) motion.


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 am starting to understand the 'chain of pain' much more now, especially after the practice we had in lecture last week."

"Position-time graphs and velocity-time graphs are becoming easier to read and understand with the help of the 'chain of pain.' The more I look at the chain of pain and the graphs, that more they appear logic-based."

"I have a much better understanding of chord and tangent slopes. A chord slope touches two different points on a graph, and therefore represents an average; whereas a tangent slope only touches one point on the graph, providing instantaneous information."

"I understand the how and why of the 'chain of pain,' though I have yet to memorize it."

"We can solve one-dimensional motion problems using kinematic equations by determining the known and unknown variables and then selecting the appropriate equation(s) to solve for the unknowns. These equations only apply when acceleration is constant."

"There are four equations we need to know regarding time, velocity, acceleration, and position. We need to know three variables per equation in order to solve for the fourth introduced variable or else it isn't solvable."

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 still confused about the 'chain of pain' chart. I am not sure what the arrows lead to and how to figure out how to solve a problem using it."

"After attending the class last Wednesday, the 'chain of pain' was not as confusing as it was earlier. The hardest part is just memorizing each process and how to get to each piece of the chart."

"The kinematic graphs are still confusing to me; I need to memorize the 'chain of pain' and how to find chord and tangent slope."

"The constant acceleration equations. I am unsure of when they are supposed to be used during certain equations."

"I am struggling with deciding which constant acceleration equation to use for these problems. It's difficult for me to confirm which quantities are given, especially with the UAV example."

"I am still a bit unsure of how to extract what the problem gives and then plug that information into the equations. I am also still a bit confused on picking the best kinematic equation. I know you pick based off of what information is given, but extracting the information proves to be a bit difficult for me."

"Not much at all. You just have to pay attention to what the problems are asking for."

Mark the level of your expertise in algebraically solving multiple equations for multiple unknowns.
None at all.   * [1]
Slight.   * [1]
Some.   ************* [14]
A fair amount.  ********************** [22]
A lot.   ****** [6]

"2012 Chrysler 300 - First Drive"
NRMA Motoring and Services
flic.kr/p/d1bozj

"The braking distance for a 2012 Chrysler 300C to slow down from 31 m/s to a complete stop is 50.3 m. Assume that the acceleration is constant as the car slows down to a stop, and always points in the opposite direction as its velocity."

From the statement of this problem, determine whether the values of these kinematic quantities are known/given or are unknown/undetermined (without solving the problem numerically).

(Only correct responses shown.)
Final horizontal position x (initial horizontal position x0 assumed to be 0): known/given. [86%]
Initial horizontal velocity v0x: known/given. [89%]
Final horizontal velocity vx: known/given. [82%]
Horizontal acceleration ax: unknown/undetermined. [75%]
Final time t (initial time t0 assumed to be 0): unknown/undetermined. [75%]

For the Chrysler 300C, the horizontal distance traveled is __________ the magnitude of the horizontal displacement.
less than.   ** [2]
equal to.   ******************************** [32]
greater than.   ******** [8]
(Unsure/guessing/lost/help!)   ** [2]

"Leichtathletik WM 2009 Berlin"
André Zehetbauer
flic.kr/p/6RmNQn

"Jamaican sprinter Usain Bolt holds the world record for the 100 m sprint, covering that (straight-line) distance in 9.58 s in Berlin, 2009. Assume that his acceleration starting from rest to when he crosses the finish line is constant, and always points in the same direction as its velocity."

From the statement of this problem, determine whether the values of these kinematic quantities are known/given or are unknown/undetermined (without solving the problem numerically).

(Only correct responses shown.)
Final horizontal position x (initial horizontal position x0 assumed to be 0): known/given. [95%]
Initial horizontal velocity v0x: known/given. [52%]
Final horizontal velocity vx: unknown/undetermined. [52%]
Horizontal acceleration ax: unknown/undetermined. [77%]
Final time t (initial time t0 assumed to be 0): known/given. [95%]

For Usain Bolt, the horizontal distance traveled is __________ the magnitude of the horizontal displacement.
less than.   *** [3]
equal to.   **************************** [28]
greater than.   *********** [11]
(Unsure/guessing/lost/help!)   ** [2]

"6 kJ Portable Pneumatic Catapult"
UAV Factory
uavfactory.com/product/21

"A portable pneumatic catapult is able to launch a Penguin B unmanned aerial vehicle (UAV) from rest to a final speed of 23 m/s along a 4.0 m rail. Assume that the rail is horizontal, and that acceleration of the UAV starting from rest to when it is launched is constant, and always points in the same direction as its velocity."

From the statement of this problem, determine whether the values of these kinematic quantities are known/given or are unknown/undetermined (without solving the problem numerically).

(Only correct responses shown.)
Final horizontal position x (initial horizontal position x0 assumed to be 0): known/given. [61%]
Initial horizontal velocity v0x: known/given. [82%]
Final horizontal velocity vx: known/given. [89%]
Horizontal acceleration ax: unknown/undetermined. [61%]
Final time t (initial time t0 assumed to be 0): unknown/undetermined. [84%]

For the UAV, the horizontal distance traveled is __________ the magnitude of the horizontal displacement.
less than.   **** [4]
equal to.   ************************ [24]
greater than.   ******** [8]
(Unsure/guessing/lost/help!)   ******** [8]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I am still a little unsure of the difference between horizontal distance and the magnitude of the horizontal displacement? I believe they are the same as long as the object is moving in one direction but not confident." (You are correct.)

"For the Usain Bolt 100-m sprint question, are we assuming that he's running on a straight or curved track? If it's curved, wouldn't that make the displacement magnitude smaller than the total distance traveled?" (If the sprint were along a curved track, then yes, the displacement magnitude smaller than the total distance traveled. However, a 100-m sprint is usually along a straight section of track, in which case the displacement magnitude would be equal to the total distance traveled.)

"When a problem says to assume acceleration is constant, does that mean it is 0?" (Not necessarily. When acceleration is zero, it is constant. But acceleration can be a constant non-zero value as well.)

"This is very basic stuff, but it is very important in order to do well in any type of physics."

"Can you please go over one of these questions including kinematic quantities in class." (We will.)

"Will Quiz 2 be structured in roughly the same way as the 'chain of pain' worksheet done in class last Wednesday?" (Yes, for several questions, the rest will be on kinematic equations and on free fall, which we will cover this week.)

"What is the best way to study for your tests?" (Study questions from old quizzes and midterms. Which is every example done in class, the majority of homework problems, and also the practice quizzes from last semester.)

20190823

Astronomy current events question: Mars' giant impact tsunamis

Astronomy 210L, fall semester 2019
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!)
Mike Wall, "This Impact Crater Was Likely Ground Zero for an Ancient Mega-Tsunami on Mars" (August 5, 2019)
space.com/mars-ocean-mega-tsunami-impact-crater.html/
Analysis of geological formations on Mars' ancient shorelines provide evidence of two separate tsunami events created by:
(A) massive landslides.
(B) marsquake tremors.
(C) giant meteor impacts.
(D) supervolcano eruptions.
(E) collapsing continental plates.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 2 students
(B) : 13 students
(C) : 22 students
(D) : 5 students
(E) : 1 student

Astronomy current events question: Earth's magnetic field reversal

Astronomy 210L, fall semester 2019
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!)
Eric Hamilton, "Earth's Last Magnetic Field Reversal Took Far Longer than Once Thought" (August 7, 2019)
news.wisc.edu/earths-last-magnetic-field-reversal-took-far-longer-than-once-thought/
Analysis of magnetic iron in ancient __________ provide evidence that Earth's most recent magnetic field reversal took far longer than previously estimated.
(A) tree rings.
(B) lava flows.
(C) petroglyphs.
(D) papyrus ink.
(E) plankton fossils.

Correct answer: (B)

Student responses
Sections 70178, 70186
(A) : 2 students
(B) : 34 students
(C) : 2 students
(D) : 0 students
(E) : 6 students