20180919

Online reading assignment: uniform circular motion

Physics 205A, fall semester 2018
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 uniform circular 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.
"Uniform circular motion is a Newton's second law case because the direction is changing, and that the net force must point towards the center."

"Circular motion is covered by Newton's second law. In order to maintain constant speed along a circular trajectory, with acceleration directed in towards the center, the net force must be exactly equal to m·v2/r, and be directed in towards the center."

"Newton's second law applies to uniform circular motion. Even as the direction is continuously changing, the acceleration always points inward towards the center."

"The 'centripetal force' is basically the net force that is required to keep an object moving in a circular motion, in where this net force is always pointed toward the center of the circle. The 'centrifugal force' is 'fictitious force' of sorts which appears to be acting on an object when really it is not. It is essentially Newton's third law in that for every action you have an equal and opposite reaction."

"'Centripetal' force means 'center-seeking' which describes a net force that is always pointing inward. 'Centrifugal force' means 'center-fleeing.'"

"I have some understanding of what we went over in class, but from the reading I have very little understanding of what is going on."

"I have not gotten to this yet, though I did spend a lot of time on our last section, reviewing and learning the problems."

"I have yet to read it because I have an organic chemistry test tomorrow."

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 find the concept of 'centrifugal force' more abstract than the type of forces we have gone over so far."

"I didn't understand 'centrifugal force' and how it's different from 'centripetal force.'"

"I got a little confused on the explanation of 'centrifugal force' being fictitious. I wasn't sure if this was saying that there is no outwards force."

"For the example scenarios you put up, I'm confused in which direction some of the net forces acting on the objects are. For example, are we to conclude that the car drifting around the track in a constant circular motion would be considered a Newton's second law case (because although speed is constant our direction is always changing) and so the net force would point to the right (towards the center of the circle)? Could some of our net force forces point in the opposite direction as to the direction the object appears to be moving? I'm a little confused on that."

"It's hard for me to conceptually and visually understand that acceleration (and net force) points inwards during circular motion. Could you please illustrate this with a drawing in class? All makes sense."

"Nothing here really! :)"

"I feel good about these concepts."

"I found most of it confusing."

For the "drifting" car (skidding around a circular track at constant speed), Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
first; is zero.   *** [3]
second; points to the left.   ********** [10]
second; points to the right.     ************************ [24]
(Unsure/lost/guessing/help!)   *** [3]


At the moment when the woman is at the bottom of her swinging trajectory (when the rope is vertical), Newton's __________ law applies to her motion, and the forces acting on her add up to a net force that:
first; is zero.   ******** [8]
second; points upwards.     ***************** [17]
second; points downwards.   ******** [8]
(Unsure/lost/guessing/help!)   ******* [7]


At the moment when the motor scooter is on the left side of the screen (traveling out at you), Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
first; is zero.   *** [3]
second; points to the left.   ************* [13]
second; points to the right.   ******************** [20]
(Unsure/lost/guessing/help!)   **** [4]


At the moment when the car is at the very top of the loop-the-loop, Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
first; is zero.   ***** [5]
second; points upwards.   ******** [8]
second; points downwards.     *********************** [23]
(Unsure/lost/guessing/help!)   **** [4]


At the moment when a person is at the right edge of the screen (traveling out at you), Newton's __________ law applies to his/her motion, and the forces acting on him/her add up to a net force that:
first; is zero.   ****** [6]
second; points to the left.   ***************** [17]
second; points to the right.   ********** [10]
(Unsure/lost/guessing/help!)   ******* [7]


At the moment when the car is at the very top of its mid-air trajectory, Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
first; is zero.   ******* [7]
second; points upwards.   **** [4]
second; points downwards.   ********************** [22]
(Unsure/lost/guessing/help!)   ******* [7]


At the moment when the skateboarder is at the very top of his mid-air trajectory, Newton's __________ law applies to his motion, and the forces acting on him add up to a net force that:
first; is zero.   ****** [6]
second; points upwards.   ***** [5]
second; points downwards.   ************************* [25]
(Unsure/lost/guessing/help!)   **** [4]


Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Centripetal force is a very cool concept! I went on YouTube and easily spent about an hour looking at different related videos!"

"So during the loop-the-loop stunt, the weight won't always affect it the same way, why is that? Would the gravitational pull change?" (No, the weight force of Earth on the object can't ever change, no matter what the object's motion is like. However, the normal force of the track on the object (if/when it is contact with the track) can change, as that is a variable force.)

"Honestly, what confused me the most was how that small girl was swinging that man by the foot in one of the presentation slides. She definitely did not have the appearance of an Olympic discus thrower." (That man is Li Wei, a performance artist that specializes in wire work stunt photography.)

"I am not totally clear about the net forces and direction, the acceleration a = v2/r always pointing towards the center (or else constant speed in a straight line), and horizontal and vertical components (e.g. if the string breaks, then there would be no inwards net force, and no uniform circular motion, such that the donut undergoes free fall--subject to Newton's second law vertically, but Newton's first law horizontally, and thus would be seen moving in a straight line." (Sounds to me like you are pretty clear on this topic.)

20180918

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

Astronomy 210, fall semester 2018
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.
"On Venus its crust is thin so it is not letting magma to push through until enough pressure builds."

"The bigger the planet, the more greenhouse gases are released into the atmosphere. Its interesting, because it all depends on how close you are to the sun, the farther the colder, the closer the warmer."

"The permafrost that's on Mars, if there's water that's frozen then there might have been life on Mars? because of that saying, 'where there's water there's life.'"

"The search for signs of water on Mars was most interesting to me because I learned a little about it last year and it makes much more sense now"

"Something I found interesting about the reading was the fact that Mars has two moons. And the history of Phobos and Deimos."

"I was not aware that Pluto had five moons, or the reasoning on why it was not considered a planet anymore."

"How the jovian planets in our system differ so much from each other, such as the gas giants and the ice giants. Then you have Earth and Mars. Due to their mass and distance from the sun, how many greenhouse gases and sunlight warmth they can hold."

"I just like the name of the gas planets: 'jovian,' it sounds like they’re happy."

"Learning about the jovian planets. I honestly didn't know that Jupiter and Saturn were grouped as "gas giants," while Uranus and Neptune are grouped together as 'ice giants,' due to their weird warm slushy ice layers."

"That different planets can have different number of moons. Such as how Saturn has 60 known moons."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Something I found confusing about the reading was the geological activity in Venus. It seems straightforward with green house gases getting trapped in the atmosphere but I'm still confused as to how it can be hotter than mercury if it’s farther from the sun."

"What makes a planet's core hot or cooler than other planets and which are cooler or hotter than others."

"How is it possible that Jupiter has so many moons? Is it because their masses attract each other?"

"It is a little confusing to keep up with all the planets and information on them without getting them mixed up."

"How to distinguish a moon from an asteroid caught in a planet's orbit."

"I'm still somewhat struggling as to why Pluto is not a planet. I do believe this will be something you might have to go over in class. And how they chose the criteria for classification."

"Why Mercury is considered a planet and not a dwarf 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 [33%]
Geologic activity, today: less than Earth [58%]
Volcanic outgassing, up until now: about the same as Earth [33%]
Heat from the sun: more than Earth [83%]
Amount of atmosphere, today: more than Earth [25%]

Identify the relative amounts of these characteristics for Mars, compared to Earth. (Only correct responses shown.)
Interior core heat, today: less than Earth [50%]
Geologic activity, today: less than Earth [42%]
Volcanic outgassing, up until now: less than Earth [75%]
Heat from the sun: less than Earth [83%]
Amount of atmosphere, today: less than Earth [75%]

Which jovian planet has the coolest interior temperatures?
Jupiter (most massive).   [0]
Saturn (most prominent rings).   ** [2]
Uranus (least active weather patterns).   [0]
Neptune (farthest from the sun).   ********** [10]
(Unsure/guessing/lost/help!)   [0]

I believe Pluto should be a planet.
Strongly disagree.   [0]
Disagree.   *** [3]
Neutral.   ******* [7]
Agree.   ** [2]
Strongly Agree.   [0]

Briefly explain your answer to the previous question (whether Pluto should be a planet).
"I still feel as if Pluto is not surrounding anything. I don't have enough knowledge on the matter but it doesn't orbit another planet."

"If it is, great! If not, get over it."

"I was so used to the fact that Pluto was a planet and then it was said not to be one so I was just used to this idea, to me does not particularly matter, the whole concept is confusing, confuses people on whether it is or is not a planet, so I stay neutral."

"It's really small and it’s way out there it's more of a space rock than a planet."

"Pluto can not clear its orbital path like all other planets do so it's not considered a planet. I didn’t put strongly disagree because Pluto is just a rock and a planet is just a word so it doesn’t really matter."

"I don't really have an opinion. I don't really care. I think space and planets in general are just crazy concepts to grasp."

"I'm pretty neutral on it. Even though growing up I was taught that it was a planet I can see why it might not be. But if we can consider gas giants planets, why not a solid frozen piece?"

"There's evidence to show that it is not a planet."

"I mean it's in our solar system for a reason, might as well be called a planet no matter the size. I don't see any harm in calling it a planet again."

"Pluto is the adopted cousin. He may not be blood, but he's family. We can't exclude him."

"I grew up believing that Pluto was a panet, and now I need more clearity in why it is not?"

"I'm still unsure on why Pluto should or should not be considered a planet and i would like further explanation on both sides."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Not much, the only thing that confused me was the geological activity of Venus."

"Can you please go over jovian planets?"

"Why do different planets have different amounts of moons?" (That depends on how much mass they have (in order to accumulate material to make and keep its moons), and also location (such as Mars being close to the asteroid belt).)

"Might we at some point consider some of Jupiter's moons planets? How often does the criteria change?" (No, because that would violate the first IAU categorization criterion. Also not as much as you might think.)

"I hope to make it to class this week! Thanks for providing in-depth presentations."

"Crossing out a wrong answer choice on quiz (for potential partial credit) really helps, thanks for making that a thing."

20180917

Online reading assignment: applications of Newton's laws (friction)

Physics 205A, fall semester 2018
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 on applications of Newton's laws (emphasizing static and kinetic friction).


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.
"If you have a constant speed and direction then Newton's first law applies. If you have a change in speed and/or direction then Newton's second law applies."

"Static friction goes against the impending relative motion between two objects and that kinetic friction goes against the relative sliding motion between two surfaces. Newton's second law can be used to find the acceleration of an object."

"I understand the difference between both static friction and kinetic friction. Static friction is the force needed to keep a stationary object at rest, for example when you go rock climbing. The static frictional forces help support someone's weight as they press against the walls of the rock and create large amounts of normal forces. Now once two surfaces begin sliding over one another then kinetic friction is produced. And kinetic friction is what slows down a moving object. For example, when you push a chair across the floor, the initial force to actually move the object requires greater force, but it takes less force to keep the object sliding."

"Static friction depends on the amount of force that is applied to stationary object. Kinetic friction is applied when an object is sliding across the floor."

"The difference between static and kinetic friction. Static friction is when an object is at rest, and once it starts to move it has kinetic friction acting on it."

"How to distinguish between Newton's first law and third law. Newton's first law relates two or more forces acting on the same object (if motion is constant), while Newton's third law relates the same force acting on two different objects."

"The coefficient of static friction is equal to or higher than the coefficient of kinetic friction."

"For the most part I seemed to understand what I read but I had to read it twice."

"I kind of understand the whole concept of friction forces, but it is still very confusing."

"Static friction has a maximum value and once that value is surpassed, then I think of it like the transfer of friction from static to kinetic. It's interesting that the maximum static friction value is independent of surface area, which I did not expect. However, the maximum value of static friction does depend on the type of surface materials."

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 need some more practice on distinguishing between newtons first and third laws in different situations. I also need to memorize what 'POF-OST-ITO' stands for."

"Static friction force--it does not make sense to me that there can be a frictional force when the object is stationary and why tugging on the object doesn't cause it to move, but I think I understand now."

"Knowing what equations to use to solve for a static/kinetic friction problem."

"I didn't understand why the magnitude of the kinetic frictional force is proportional to the magnitude of the normal force."

"The relationship between friction and normal force."

"Difference between static and kinetic friction."

"What I found to be the most confusing from the assigned reading was the difference between static and kinetic friction. I think that static friction is applied force to keep an object stationary and then kinetic friction is when two things slide over each other, but I am not sure."

"All of the equations that were given in the book, there was just a lot of information thrown out all at once, but I should be able to understand it after I have to use it for a problem."

"Pretty much this whole chapter was confusing. I didn't take as much time reading it as the other chapters though, so that could play a part in that."

"I found it confusing knowing which law to apply in terms of Newton's first law or Newton's third law, but it was better explained in class and I understand now."

What is the meaning of the "normal" in the "normal force?"
"'Normal' means perpendicular to the surface."

"The 'normal' comes from the fact that it is always there when an object is in contact against a surface?"

"Any forces already acting on the object of concern?"

"'Normal' force usually refers to forces that act naturally in a sense?"

"Does it mean 'instantaneous?'"

The SI (Système International) units of the static friction coefficient µs and the kinetic friction coefficient µk are:
"The coefficients are unitless."

"Trick question, there are none."

"I am truly confused."

Identify the magnitude of the static friction force fs for each of the following situations of a box that is initially stationary on a horizontal floor. (Only correct responses shown.)
No external horizontal forces applied to it, so it remains stuck to the floor:
fs = 0. [83%]

An external horizontal force applied to it, but still remains stuck to the floor:
fs = some value between 0 and µs·N. [68%]

An external horizontal force applied to it, at the threshold of nearly becoming unstuck:
fs = µs·N. [71%]

Identify the magnitude of the kinetic friction force fk for each of the following situations of a box that is already sliding across a horizontal floor. (Only correct responses shown.)
No external horizontal forces applied on it, so it slows down:
fk = µk·N. [22%]

An external horizontal force applied in the forward direction, but not enough to keep the box going so it still gradually slows down:
fk = µk·N. [17%]

An external horizontal force applied in the forward direction, just enough to keep the box going at a constant speed:
fk = µk·N. [39%]

An external horizontal force applied in the forward direction, enough to gradually increase the speed of the box:
fk = µk·N. [37%]

An external horizontal force applied in the backwards direction, such that the box slows down:
fk = µk·N. [22%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I struggled with these questions and probably need some more explanation on them."

"I don't understand how to determine which forces cancel out. Also, if the net force is negative, what would happen?" (Determining which forces are exerted on an object depends on the wording of the problem. Deciding whether these forces cancel or not depends on whether the motion is constant or changing. If a net force is negative, then it points in the negative direction (depending on how you defined your positive direction); but usually we denote magnitudes of forces (keeping them all positive), and explicitly denoting their direction in words (left/right/up/down) or arrows.)

"When would fk = some value between 0 and µk·N? Is that possible?" (That would never be possible. The kinetic friction force (assuming that the object is already unstuck, and has motion (constant or changing) would always be equal to µk·N.)

"Could you please go over what the values of static and kinetic frictional forces mean? I'm having a hard time grasping the concept of when kinetic friction force equals zero, and so on." ("Kinetic" means "in motion," so if the object is still stuck to a surface, then kinetic friction force is zero.)

"I could not find the presentation preview." (There were no presentation slides for this topic; just the textbook chapters.)

"You are really helpful going over the chapters and material in class. It helps me out a lot." (You're helping me out a lot by telling me what you specifically understand or are confused about when I prepare for each class.)

20180914

Astronomy current events question: bright boomerang-shaped feature in nebula IRAS 05437+2502

Astronomy 210L, fall semester 2018
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!)
Karl Hille, "Hubble’s Lucky Observation of an Enigmatic Cloud" (August 31, 2018)
nasa.gov/image-feature/goddard/2018/hubbles-lucky-observation-of-an-enigmatic-cloud
A bright boomerang-shaped feature observed by the Hubble Space Telescope in the nebula IRAS 05437+2502 may be caused by:
(A) neutron star pulses.
(B) a nearby type II supernova.
(C) a star ejected from its cluster.
(D) cosmic microwave background radiation.
(E) colliding white dwarfs.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 6 students
(B) : 8 students
(C) : 8 students
(D) : 3 students
(E) : 1 student

Astronomy current events question: formation of exoplanet PDS 70b

Astronomy 210L, fall semester 2018
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!)
Susanna Kohler, "Planet Formation Caught in the Act" (August 17, 2018)
aasnova.org/2018/08/17/planet-formation-caught-in-the-act/
High-resolution images of the exoplanet gas giant PDS 70b by the Magellan Clay Telescope in Chile provide evidence for:
(A) its extensive ring system.
(B) colliding with its star.
(C) potentially habitable moons.
(D) becoming a red dwarf.
(E) still collecting hydrogen.

Correct answer: (E)

Student responses
Sections 70178, 70186
(A) : 5 students
(B) : 3 students
(C) : 6 students
(D) : 3 students
(E) : 9 students

Astronomy current events question: age and history of asteroid Itokawa

Astronomy 210L, fall semester 2018
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!)
Press release, "Particles Collected by Hayabusa Give Absolute Age of Asteroid Itokawa" (August 8, 2018)
resou.osaka-u.ac.jp/en/research/2018/20180808_1
Analysis of __________ from the Japan Aerospace Exploration Agency's Hayabusa spacecraft provide evidence for the age and history of asteroid Itokawa.
(A) stray particles.
(B) surface crater density.
(C) radar pulses.
(D) orbital fluctuations.
(E) magnetic fields.

Correct answer: (A)

Student responses
Sections 70178, 70186
(A) : 17 students
(B) : 5 students
(C) : 3 students
(D) : 1 student
(E) : 0 students

20180913

Astronomy quiz question: morning star Mars?

Astronomy 210 Quiz 2, fall semester 2018
Cuesta College, San Luis Obispo, CA

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


At sunrise, Mars will be:
(A) low over the east horizon.
(B) somewhere high up in the sky.
(C) low over the west horizon.
(D) not visible in the sky.

Correct answer (highlight to unhide): (D)

If a line is drawn from Earth to the sun, the observer at sunrise (6 AM) is located perpendicular to that line.


Everything below that line would be below the horizon, such that Mars is not visible at sunrise. (Note that Jupiter will also not be visible at sunrise.)

Section 70158
Exam code: quiz02Sl3I
(A) : 7 students
(B) : 3 students
(C) : 4 students
(D) : 22 students

Success level: 62% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.80

Section 70160
Exam code: quiz02N3r1
(A) : 6 students
(B) : 2 students
(C) : 4 students
(D) : 4 students

Success level: 26% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.75

Astronomy quiz question: Jupiter's retrograde motion

Astronomy 210 Quiz 2, fall semester 2018
Cuesta College, San Luis Obispo, CA

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


Jupiter is __________ retrograde motion.
(A) about to start.
(B) in the middle of.
(C) just completing.

Correct answer (highlight to unhide): (C)


Retrograde motion occurs for Jupiter when the sun, Earth, and Jupiter are aligned (Mars in opposition). Drawing in lines from the sun to Earth and the sun to Jupiter indicates that Earth (which travels faster along its inner orbit), has already overtaken Jupiter (which travels slower along its outer orbit), thus Jupiter has already completed its retrograde motion.

Section 70158
Exam code: quiz02Sl3I
(A) : 18 students
(B) : 7 students
(C) : 11 students

Success level: 32% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.40

Section 70160
Exam code: quiz02N3r1
(A) : 6 students
(B) : 7 students
(C) : 3 students

Success level: 20% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.25


(Animation from marsprogram.jpl.nasa.gov)

20180912

Astronomy quiz archive: eclipses/history of astronomy

Astronomy 210 Quiz 2, fall semester 2018
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz02Sl3I


Section 70158
0- 8.0 :   * [low = 4.0]
8.5-16.0 :   ********
16.5-24.0 :   *******
24.5-32.0 :   ********* [mean = 24.8 +/- 9.6]
32.5-40.0 :   ********** [high = 40.0]


Section 70160, version 1
Exam code: quiz02N3r1


Section 70160
0- 8.0 :  
8.5-16.0 :   ******** [low = 12.0]
16.5-24.0 :   **** [mean = 19.3 +/- 6.8]
24.5-32.0 :   **** [high = 28.5]
32.5-40.0 :  

Online reading assignment: atmosphere problems, Earth, the moon, Mercury (SLO campus)

Astronomy 210, fall semester 2018
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 problems caused by the atmosphere for telescope observing, Earth, and the impacted worlds: the moon, and Mercury.

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 this year that the James Webb Space Telescope (JWST) is being launched this year, if it hasn't already."

"I found the telescope on the back of the re-purposed plane to be very interesting; it's useful to being able to get a better view of the sky without have to have a telescope in space."

" The analogy used to describe air turbulence was really easy to grasp given how relatable it is and how much sense it makes. I did not know this was why stars 'twinkled.'"

"I've always wondered why stars twinkled and to understand that the reason for that is because we are watching them through the atmosphere."

"The fact that stars twinkle because of the Earth's atmosphere and just them not twinkling on their own."

"Atmospheric turbulence, because I didn't know that the atmosphere and air could distort our view of the night sky."

"The idea of putting a telescope in space. was super interesting to me. I know there are other cheaper solutions but I can't get the idea out of my head."

"Thinking about other planets and well, space in general blows my mind because of the extensiveness of it all. I feel like there's so much to learn/find out about Earth still and it's really just an extremely small fraction of what else is out there, so in addition to Earth, learning about other planets in our solar system will be really fun."

"Continental drift was pretty interesting and how our continents are able to move."

"How the greenhouse effect is mostly nature-driven."

"That we can still be able to identify the age of certain features on a planet despite not knowing exactly how they are made."

"The similarities about the moon and Mercury. I did not know much about Mercury before the reading."

"I found the large-impact hypothesis to be quite interesting. The moon is just formed from the debris of this collision. Topics like this and the big bang hurt my brain a tad, and then I go through a minor existential crisis."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I found the basics of the telescope a bit difficult to grasp because it is easy to get confused between all the terminology."

"I could use some more clarification on telescopes and all of their aspects."

"I also found atmospheric turbulence confusing because I am not really sure how the atmosphere distorts our view."

"Adaptive optics was confusing to me, I just do not think I was understanding how the mirrors helped focus the images."

"The greenhouse effect was a bit confusing to me."

"Whether the curving ridges are older or newer than the lava lowlands on Mercury."

"Could you go over the right answers for oldest to youngest features of the moon and Mercury?"

"I found it confusing that Mercury had more iron than expected because it seems strange to me."

"Confused on the large-impact hypothesis for Mercury."

"I didn't really find anything confusing. "

A large modern optical telescope in outer space would have images with better __________ than a comparable ground-based telescope.
brightness.   ****** [6]
resolution.   ************ [12]
magnification.   [0]
(None of the above choices.)   [0]
(Two of the above choices.)   ***** [5]
(All of the above choices.)   **** [4]
(Unsure/guessing/lost/help!)   [0]

Stars to appear to "twinkle" in the night sky because of...
"The stars appear to twinkle due to Earth's atmosphere when the light rays enter. In order to look at it without seeing the twinkle you could use a telescope that is in outer space...if you manage to get access to it."

"The interference of the atmosphere and the movement of all the air above us."

"Light pollution and the fact that all of their light must pass through the substances in Earth's atmosphere."

"When light of a star travels from the sky to Earth, the light gets moved around from wind and particles in the air, making them look as if they are twinkling."

"Turbulence or disturbances in the atmosphere cause rippling which distort astronomical viewing."

Identify how carbon dioxide enters and how it is taken out of Earth's atmosphere.
(Only correct responses shown.)
Enters atmosphere from: volcanoes [63%]
Taken out of atmosphere by: oceans [58%]

Identify the oldest (longest ago) to the youngest (most recent) features on the moon.
(Only correct responses shown.)
Craters partially filled in with flat lava plains: oldest (formed longest ago) [52%]
Flat lava plains: middle [37%]
Craters on top of flat lava plains: youngest (formed most recently) [67%]

Identify the oldest (longest ago) to the youngest (most recent) features on Mercury.
(Only correct responses shown.)
Large crater basins: oldest (formed longest ago) [59%]
Lava-filled lowlands: middle [52%]
Long curving ridges: youngest (formed most recently) [54%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I'm a bit lost on telescopes. Do you think we could go over that topic more in class?"

"Why we don't have most of our telescopes in space if that's where we get the best view of the stars?" (It's super-expensive to build, launch, and maintain a telescope in space. For optical telescopes, the effect of atmospheric turbulence has been solved by using adaptive optics, so the money involved in putting up a small telescope in space can now be used to build a much bigger (and better light-gathering and resolving power) telescope on the ground. For other forms of light, though, it will still be necessary to put telescopes in space (or be flown very high up in the atmosphere) in order to get around the absorption of the atmosphere.)

"Do you own a telescope?" (No, since I get to use the telescopes at school whenever I want.)

"Thanks again for giving us the opportunity to see the dome rotate in the observatory, that was a really cool experience."

"Why can astronauts visit the moon, but not Mercury?" (There's already a huge energy cost to leave Earth to get to the moon; but an even more energy would be required to leave Earth's orbit, start getting closer into the sun toward Mercury, and then slow down enough such that Mercury's gravity will take hold--NASA's MESSENGER probe to Mercury took more than six years to do that journey.)

"You'll never find a small gas world. How exactly are relatively smaller planets unable to become jovian worlds?" (You need enough gravity (mass) to collect and hold onto hydrogen and helium. Earth's gravity isn't enough; that's why hydrogen and helium float upwards and will eventually escape into space from Earth's atmosphere.)

"What is the farthest planet we can travel to other than Pluto?" (Uh, Pluto's not a planet--it's a dwarf planet in the Kuiper belt (the icy outer belt of the solar system). In any case, NASA's New Horizons spacecraft has passed Pluto already, and is currently its way to "Ultima Thule," another Kuiper belt object further out.)

"When will we be discussing topics like the big bang?" (Later this semester--that's Quiz 7 stuff.)

"Do you give us a study guide for each exam?" (Yes--and there will be a review session for each exam as well.)