Online reading assignment question: advice to self for next semester

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. The following question was asked after the last lecture, but prior to the final exam.

Give a piece of advice to yourself at the start of next semester on what you should do (the same, or differently) in order to succeed in Physics 205A/B (or similar science courses). (Graded for completion.)

"While spending a lot of time with the material is great, my goal for next semester is to find study partners in Phys 205B. This has worked great for me in other science and math classes and I wish I had found people in class to study with for Phys 205A."

"Just do the homework and review the labs before class."

"Don't give up early on. It will look like you have a low grade early on in the class, but it works out to be a lot higher. Get information on how the point system works. The first week of class you need to figure out his website. Do it and make sure you understand it. Do the homework; don't freak out if you can't understand the assigned text or problems. Just complete the homework and show up to class, stay over for office hours if you are still confused. Labs are fairly easy and a good grade buffer show up to all of them. The labs are interesting, visual, and help you better understand concept questions on the quizzes. Midterms were hard for me. Just do the example problems and study how the point system works for each midterm example problems. Find a study partner or make a friend so that you can both keep each other up to date on what needs to be done. His website calendar does not change. None of the dates change for tests or quizzes nor do the homework assignments. Nothing should come as a surprise in the class with his calendar. The quizzes are very DSPS-friendly. You make your test-taking calendar in the first few weeks and don't have to worry about turning in a new DSPS sheet every other week for a quiz. It is a one-and-done thing. P-dog is great, it's just the first few weeks are confusing and his website you will hate at first, towards the end you will love it. Show up to all the classes! His worksheets help with quiz scores."

"Put in more effort, focus more, and try to ask questions!"

"Make sure you do all the homework, reading, labs and study for your quizzes."

"Physics is one of those classes where the amount of work you put in directly dictates the results you get. Study hard, pay attention in class, and make sure you understand everything cause information often resurfaces. read those chapters ahead of time."

"Actually do all the assignments because they do help a lot. I noticed that when I did the reading and homework assignments it was a lot easier to follow the next class."

"Just stay on top of the homework and the reading. Also to do the lab reports sooner in the week so I'm not as stressed about them."

"Study, do the homework and reading assignments, go to class and pay attention."

"Practice, practice, practice solving all the example problems given to you. Also, it helps a lot to write out short answers on what you did."

"Always, always do the work. It's easy points and can make the difference when passing the class."

"Rack up all the points you can before tests because you never test well. Stay organized and remember all of the reading assignments and post labs. Every point is worth it."

"Stay up on the homework, go to lab, take good notes in lecture and stay organized."

"I would do all of the reading assignments and homework. Go to the class and lab."

"I would say to continue doing what you're doing, but could spend more time on the homework problems which I feel like would help on the quizzes."

"I suggest the future students take notes while reading (the night before lecture), to better understand the material. Take notes again in class and ask QUESTIONS!"

"Do the dang reading assignments!!!!!!"

"Stay on top of homework! You killed yourself this semester with that."

"The grade you get is how much time you put in."

"Study the concepts more than how to do them."

"Disregard trying to read the textbook and read the blog posts carefully instead because the book is not user-friendly."

"Try to go to office hours if my schedule has time to do so."

"Do all reading assignments and homework early so you don't forget when you are studying for all classes! Print out calendar from the waiferx.com course website and mark off upcoming/completed assignments."

"Read everything on the waiferx.com course website because there are no reminders and it is not organized like Canvas."

"Keep up on the pre-labs and post-labs along with the homework assignments. They are super-mellow so there really shouldn't be a reason not to do them."

"Show up to all the classes and after class go over the problems/worksheets until you understand them."

"Keep doing the problems until I understand them completely."

"Next semester I need to go into office hours if I have topics that confuse me instead of only trying to figure it out myself."

"Do a lot of example problems with varying variables missing in order to prepare."

"Either write down or make a document of all the practice and homework problems so they can be easily referenced!"

"You're doing great!"

Physics quiz question: dimensional expansion of aluminum rod

Physics 205A Quiz 7, fall semester 2018
Cuesta College, San Luis Obispo, CA

An aluminum bar (linear expansion coefficient 2.3×10^–5 K^–1) has a length of 0.500 m, and a cross-sectional area of 4.0×10^–4 m² at room temperature (20.0° C). As the temperature of the bar is raised, its __________ will increase.
(A) length.
(B) cross-sectional area.
(C) (Both of the above choices.)
(D) (Neither of the above choices.)

Correct answer: (C)

The relation between the change in length (along any dimension) ∆L due to a temperature change ∆T is given by:

α·∆T = ∆L/L.

With a temperature increase, the length, width, and height of the bar will all proportionally expand, such that both the length and the cross-sectional area of the bar will increase.

Sections 70854, 70855
Exam code: quiz07PeA7
(A) : 25 students
(B) : 3 students
(C) : 22 students
(D) : 0 students

Success level: 44%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.13

Physics quiz question: comparing temperature changes

Physics 205A Quiz 7, fall semester 2018
Cuesta College, San Luis Obispo, CA

A 0.50 kg iron sample (600 K initial temperature) and a 0.75 kg iron sample (300 K initial temperature) are brought in contact with each other to reach thermal equilibrium. Ignore heat exchanged with the environment. Specific heat of iron is 452 J/(kg·K). After thermal equilibrium is reached, the __________ iron sample will have experienced the larger change (increase/decrease) in temperature. (A) 0.50 kg.
(B) 0.75 kg.
(C) (There is a tie.)
(D) (Not enough information is given.)

Correct answer (highlight to unhide): (A)

The transfer/balance energy conservation equation for this system is given by:

Q_ext = ∆E_{0.50 kg} + ∆E_{0.75 kg},

and since there is no heat exchanged with the environment, Q_ext = 0, such that:

0 = m_{0.50 kg}·c_iron·ΔT_{0.50 kg} + m_{0.75 kg}·c_iron·ΔT_{0.75 kg},

and:

–m_{0.50 kg}·ΔT_{0.50 kg} = m_{0.75 kg}·ΔT_{0.75 kg}.

From inspection, since m_{0.50 kg} < m_{0.75 kg}, then –ΔT_{0.50 kg} > ΔT_{0.75 kg}, and thus the 0.50 kg iron sample will under a larger temperature change (which would be a decrease in temperature) than the 0.75 kg iron sample (which would increase in temperature).

Sections 70854, 70855
Exam code: quiz07PeA7
(A) : 28 students
(B) : 3 students
(C) : 19 students
(D) : 0 students

Success level: 56%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.72

Physics quiz question: thermal resistance of cork coaster

Physics 205A Quiz 7, fall semester 2018
Cuesta College, San Luis Obispo, CA

A coaster is made from a square piece 
(12 cm × 12 cm) of cork (thermal conductivity 0.040 watts/m·K)[*]. Heat is conducted through its thickness of 0.50 cm. The thermal resistance of this cork coaster is:
(A) 2.9×10^–6 K/watt.
(B) 0.014 K/watt.
(C) 0.12 K/watt.
(D) 8.7 K/watt.

[*] corkstore24.co.uk/properties-of-cork-material/.

Correct answer (highlight to unhide): (D)

The thermal resistance R of an object can be related to its thermal conductivity κ by:

R = d/(κ·A),

where d is the thickness of the object that heat must conduct through, and A is the cross-sectional area, such that the thermal resistance is:

R = (0.0050 m)/((0.040 watts/m·K)·(0.12 m)·(0.12 m)) = 8.680555555... K/watt,

or to two significant figures, the thermal resistance of the coaster is 8.7 K/watt.

(Response (A) is d·κ·A; response (B) is d·κ/A; response (C) is κ·A/d.)

Sections 70854, 70855
Exam code: quiz07PeA7
(A) : 3 students
(B) : 5 students
(C) : 5 students
(D) : 37 students

Success level: 74%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73

Physics quiz question: comparing rates of radiated heat

Physics 205A Quiz 7, fall semester 2018
Cuesta College, San Luis Obispo, CA

Two solid blocks with the same temperature, but different surface areas and emissivities are placed in separate, room temperature (290 K) environments. Ignore conduction and convection heat transfers to/from the environment. The __________ object radiates more heat per time to the environment.
(A) smaller, e = 0.1.
(B) larger, e = 0.9.
(C) (There is a tie.)
(D) (Not enough information given.)

Correct answer (highlight to unhide): (B)

The power radiated by an object (where the negative sign indicates that heat is continuously leaving its surface) is given by:

Power = –e·σ·A·T⁴,

where the Stefan-Boltzmann constant σ = 5.670×10^–8 watts/(m²·K⁴) and the surface temperatures T = 600 K are the same for both objects.

For the smaller, lower emissitivity (e = 0.1) object, the power radiated is:

Power_smaller = –(0.1)·σ·A_smaller·(600 K)⁴,

and for the larger, higher emissivity (e = 0.9) object, the power radiated is:

Power_larger = –(0.9)·σ·A_larger·(600 K)⁴,

and from inspection, since 0.1 < 0.9 and A_smaller < A_larger, then the larger, higher emissivity object will radiate heat at a higher power rate than the smaller, lower emissivity object.

Sections 70854, 70855
Exam code: quiz07PeA7
(A) : 16 students
(B) : 32 students
(C) : 2 students
(D) : 0 students

Success level: 64%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.37

Astronomy quiz archive: Milky Way, nucleosynthesis, cosmology

Astronomy 210 Quiz 7, fall semester 2018
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz07S4rA


Section 70158

0- 8.0 :	* [low = 4.0]
8.5-16.0 :	****
16.5-24.0 :	******
24.5-32.0 :	************* [mean = 25.9 +/- 8.6]
32.5-40.0 :	******* [high = 40.0]

Section 70160, version 1
Exam code: quiz07N4Ta


Section 70160

0- 8.0 :
8.5-16.0 :	*** [low = 14.5]
16.5-24.0 :	******* [mean = 22.7 +/- 5.7]
24.5-32.0 :	******
32.5-40.0 :	* [high = 36.0]

Online reading assignment: origin of life, are we alone? (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 the origin of life, a "Here Is Today" timeline, LEGO® washing tips and the extraterrestrial hypothesis.

Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.

"Oxidation is interesting and confusing because it's erosion but more complicated."

"I love the idea of life, there is no way we are alone in the universe."

"I think the whole chapter was interesting due to the fact that the life on other planets is a huge question that the human race has been curious about for ages. Defining life is another interesting topic due to the fact that extra terrestrials might be considered 'alive' but in a completely different way than the typical human would think."

"How the timeline of all of time from the birth of the solar system to the the start of humans seems to make you feel so short-lived. Almost as if what you are or what you have done doesn't really matter in the grand scheme of time."

"How from now on, every consecutive lifeform on Earth should evolve faster and faster."

"The Drake equation was interesting--it is a reasonable explanation in a quantifiable way that explains the chances of other intelligent life may exist in the universe."

"Something that I found interesting was the debate and idea of their being other life in the universe...we are not alone."

"Watching the timeline video and how it moved back through time to give perspective on how long a period humans have been around compared to the solar system. "

"How little the line is for humans on the Here is Today timeline."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.

"I found nothing confusing, life exists out there."

"The definition of life, due to the fact that it is always heavily discussed."

"What kind of civilizations we are looking for with the Drake equation."

"DNA because I haven't studied biology in several years."

"The Drake equation confused me. Exactly what is it and what can it tell us."

"The theory of chemical evolution to be confusing. I find it hard to believe that biogenesis could begin from inorganic matter. If this could happen on Earth under the circumstance that Miller and Urey produced in the lab, then it's more likely that life could have evolved in similar situation in other places in the universe."

"Nothing was confusing."

"Something I found confusing was the process of evolution and the lengths of time for significant events to occur on Earth. "

"The origin of life, because it's hard for me to comprehend the vast size and how everything around us just started with a few molecules, it's amazing."

"The Drake equation is really confusing and can't wrap my head around the whole equation."

Briefly describe a difference between life and non-living things.

"living things require a constant intake of energy and cease to be alive when it stops."

"Amino acids are the basis of all life. Non-living things don't have amino acids."

"The biggest difference would be that living things are able to make copies of themselves."

"Assuming that life is only capable through the presence of carbon, that would be the difference between living and non living things. Carbon needs to be present to bind together and form the lifeforms."

"Life is the ability to manipulate your environment and create more generations of yourself to manipulate their environments. Non-living things are just there and can not manipulate anything."

"Life is different from non-living things because in order to be living you must contribute to the environment such as creating, destroying and also being able to adapt to the changes in the environment"

"Life can reproduce itself and it contains DNA."

"Living things contain cells, non-living things are acellular."

"Something is said to be alive if it extracts energy from its environment, maintains itself, and can change its environment in order to survive and reproduce new life. Inamimate matter, in contrast, can not do any of these functions that a living thing can."

"Living things can grow and reproduce, non-living things can't do anything."

"Life is something that is alive and its life can come to an end at any point. Non-living things don't, and are dead basically. "

"Living things interact with their environment. they also manipulate it."

"Living things are: things that can manipulate the environment and produce another generation where non-living things are objects that do not grow, reproduce or seem to breathe."

"A living thing should manipulate its environment."

"Living things can grow and use other molecules to sustain there ability to grow and non-living things don't need to grow and just stay still with non moving molecules."

"Non-living things are chemically made and life is complex molecules."

Rank the amounts of time it takes for each of the following to have occurred on Earth.
(Only correct responses shown.)

Time after the formation of Earth for single-cell life to arise: a medium amount of time (about 1 billion years) [54%]
Time for the first types of simple single-cell life to evolve into fishlike creatures: the longest amount of time (about 3 billion years) [84%]
Time for fishlike creatures to evolve into more complex land-based animals today: the shortest amount of time (about 0.5 billion years) [58%]

How important is it to you to know whether or not there may be life elsewhere other than on Earth?

Unimportant.	* [1]
Of little importance.	*** [3]
Somewhat important.	***** [5]
Important.	***** [5]
Very important.	*****[5]

Briefly explain your answer regarding the importance of knowing whether there may be life elsewhere other than on Earth.

"It would be so far in the past anyway that it may not matter."

"We need to know if we are alone in this universe. We are incredibly lucky if we are."

"It's not very important to me because, unless we can visit them, it won't change much."

"They are many questions/issues that have arisen in our society that do not have permanent solutions. Such as perfect renewable energy and similar scenarios. Perhaps meeting with another intelligent life form could offer other solutions? Also I just think it's something that would be really cool to see, assuming it isn't like the movie Independence Day."

"I think it is somewhat important to know if there is other life because we have been wondering for so long, just imaginening the possibility of sharing something different not just in culture but in worldly way."

"I believe it's very important to know what other type of lifeforms are in the universe mainly because that would be an unbelievable discovery and we could possibly learn more about them and how they are able to survive."

"It is not something I think about a lot, but it would be very interesting to know."

"There is much life on this planet now that life somewhere else should not surprise me. The vastness of the universe will no doubt contain more life in many forms that I have no doubt about it. It will only be a matter of time."

"I think that would be one of the coolest things ever to find out if we are alone or not."

"I think about it a lot. To know whether or not there is life somewhere other than Earth would be the most fascinating thing we have ever learned in history. As of now, whatever is on Earth is all we know that lives. I, myself would be extremely ecstatic to learn more about potential life on another planet."

"I believe that our universe is so ridiculously ginormous that I want to believe there are other species and I want to know so badly how similar they are to us and how they are surviving. Also how their lifestyle is in comparison to our world today."

"It's not something that keeps me up at night, but it's fascinating to think about."

"It is somewhat important to know whether or not there is life elsewhere other than Earth since then it will add spice to our lives and it means that there is more to life then just Earth."

"It's important for the continuation of the human race and for science."

"Due to the distance there could be life right now on another planet, but we will more than likely not find out in my lifetime."

"Id like to know if there were other organisms out there just like us because we would be able to befriend them and learn things about how the universe works that maybe we don't know ourselves If something happened way longer down the road then I could see it being important."

Which type of star would be least likely to have a planet that could support life?

Massive.	********* [9]
Medium-mass.	*** [3]
Low-mass (red dwarf).	****** [6]
(Unsure/guessing/lost/help!)	* [1]

Briefly explain your answer to the previous question (type of star least likely to have a planet that could support life).

"Massive stars generate too much heat for the Goldilocks zone to be available."

"Complex life takes a long time to form and massive stars don't live very long."

"I believe a low-mass red dwarf would be incapable of hosting life on a nearby planet due to the lower temperatures and how hard it would be for complex life forms to rise from that."

Describe what the Drake equation is used for.

"It is used to estimate the total amount of communicative civilizations in our galaxy."

"It's used to narrow the search for life in the universe."

"It is used for calculating the chance of life elsewhere."

"I am confused about this."

"So lost."

In your opinion, how plausible is it that the Chilbolton message is a reply from extraterrestrials?

Implausible.	*** [3]
Not very plausible.	********** [10]
Somewhat plausible.	***** [5]
Very plausible.	* [1]
(Unsure/guessing/lost/help!)	[0]

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

"I watched a documentary about 10 years ago about these three British guys that wen around and made the crop circles that we saw."

"Do you think that the Chibolton message is a hoax or a message of some kind?"

"Because the universe is infinite, isn't it guaranteed that there should be life on other planets? Do you think there is life somewhere else in this universe?"

"What do you think is the likelihood of intelligent life evolving in the universe? Do you think intelligent life is rare or abundant?"

"Do you think there are aliens?"

"How do you feel about the movie Interstellar?"

"Do you think the Chilbolton message is a reply from extraterrestrials?"

"Dang, this will be the last class."

Physics quiz archive: temperature, thermal equilibrium, heat transfers

Physics 205A Quiz 7, fall semester 2018
Cuesta College, San Luis Obispo, CA
Sections 70854, 70855, version 1
Exam code: quiz07PeA7



Sections 70854, 70855 results

0- 6 :	** [low = 6]
7-12 :	****
13-18 :	***********
19-24 :	********************** [mean = 20.8 +/- 6.0]
25-30 :	************ [high = 30]

Online reading assignment: origin of life, are we alone? (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 the origin of life, a "Here Is Today" timeline, LEGO® washing tips and the extraterrestrial hypothesis.


Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.

"The Miller-Urey Experiment, it explained how how organic compounds could have formed."

"The possibility of other life in the universe."

"Just the concept of time and duration that can view how old things are."

"How there may be life beyond our planet Earth, this topic really interests me. The fact that we may be wondering if there is life beyond us and elsewhere someone or something may be wondering the same thing."

"The debate and various explanations of life's origins is always really interesting to me. It's a wide and mind-blowing kind of a subject to talk about, so that's always fun."

"The Drake equation seems interesting to me just because owe can have factors can be used to find many things about the Milky Way."

"Knowing about the origins of life; I thought it was cool how we it started off with molecules and we end up being ourselves."

"Something I found interesting was the fact that we know that the fist single-cell organism dates back around 3.4 billion years ago. It amazes me how were able to detect our cells ages so far back!"

"The idea that alien life is really out there is so cool cuz aliens are cool in themselves."

"I really liked the hereistoday.com website. It was interesting to see the evolution of life on a timeline."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.

"So is there life on other planets?"

"Something I found confusing about the reading was the Chilbolton reply--I'm not too sure if it's be plausible or not."

"The process of evolution and secondly if there are truly other lives in the universe."

"Lengths of time for significant events to occur on Earth--my confusion should be evident due to my answers to the following questions."

"The Drake equation--I found it confusing because I suck at math and I panicked."

"Something I found confusing is exactly how they're able to detect cells that far back and how they determine how old it was."

"How do we know the crop circles aren't a hoax?"

"The Drake equation was a bit confusing because there was a lot to it and there isn't a way to find a for sure answer yet."

"The Drake equation wasn't confusing it just has so many parts that make it up, and it doesn't even have an answer to the equation."

"The Drake equation. Mixing math with science is not my thing!"

Briefly describe a difference between life and non-living things.

"Living things breath oxygen, use energy, reproduce probably. Non-living things do not."

"Non living things can be described as objects that do not show any signs of being alive, they do not grow, move or reproduce. A living thing or life is something that does grow, reproduce, is active. "

"A living thing should be able to adapt in its own life time or through changes in generations, a non-living thing has no adaption or changes."

"Living things have cells?"

"Living things are described as something that is able to manipulate, and survive the environment, and is able to create a new generation. If not it is considered non-living."

"To be living it should be able to manipulate its environment, in order to grow and make a new generation. It should also be able to survive changes, and adapt. Non-living things can not do this."

"Something that is living has the ability to take action, or manipulate something on Earth. Non-living things are unable to manipulate."

Rank the amounts of time it takes for each of the following to have occurred on Earth.
(Only correct responses shown.)

Time after the formation of Earth for single-cell life to arise: a medium amount of time (about 1 billion years) [62%]
Time for the first types of simple single-cell life to evolve into fishlike creatures: the longest amount of time (about 3 billion years) [100%]
Time for fishlike creatures to evolve into more complex land-based animals today: the shortest amount of time (about 0.5 billion years) [62%]

How important is it to you to know whether or not there may be life elsewhere other than on Earth?

Unimportant.	[0]
Of little importance.	* [1]
Somewhat important.	****** [6]
Important.	** [2]
Very important.	**** [4]

Briefly explain your answer regarding the importance of knowing whether there may be life elsewhere other than on Earth.

"We need to know, that way we can coexist peacefully."

"Cause if there is life else where, we can learn from them and become allies."

"It's an interesting and exciting idea, don't get me wrong. But until we find out that Tatooine exists, I'm just gonna try to focus on trying to understand the planet we already got, Earth. There's so much we still need to understand here, finding another planet full of life would make things more complicated. As it is projected in the movies, i feel like our governments would handle alien intelligence poorly and stupidly. Sorry guys, but let's get real here. I'm a 'down to Earth' guy anyways"

"To me it is somehwhat important just for my own curiosity. I think I want to know if there is life out there but also if I did not know I would be okay with that."

"As Carl Sagan said whether we're alone in the the universe or not both odds are terrifying but still the curiously of other life and how they act and operate is very intriguing."

"It would be important if that were true, though I don't feel like we will find out in my lifetime."

"I believe that finding out if other life exists elsewhere is important. I don't however believe that I will live to see us find that information out."

"It's creepy and also scary, but incredible fascinating. It's one of those things that you don't really have to know in order to live peacefully, but also something that makes you not want to die without knowing."

"Well, I won't die if I never get confirmation of extra-terrestrial life. But it would be neat."

"That means we're not alone."

Which type of star would be least likely to have a planet that could support life?

Massive.	**** [4]
Medium-mass.	** [2]
Low-mass (red dwarf).	*** [3]
(Unsure/guessing/lost/help!)	**** [4]

Briefly explain your answer to the previous question (type of star least likely to have a planet that could support life).

"Massive star won't live long."

"Low-mass, because it's too old, and it would be nearing the end of its main sequence."

"I'm debating between massive and low-mass stars. They're both really extreme in their own ways (massive too hot, low-mass too cold). I'm just making a rough guess; I'm sure this will be cleared up in class."

"I'm not quite sure which one would least likely to have a complex form of life and i would like to have this clarified."

"I have no idea."

"I was unsure of this question, need explanation."

Describe what the Drake equation is used for.

"Probability of finding other life in our galaxy."

"The Drake equation helps estimate the number of active, communicative alien civilizations in our Milky Way."

"Used to estimate the number of other possible advanced technologies out in the Milky way that we can actually communicate with or at least contact."

"Unsure."

In your opinion, how plausible is it that the Chilbolton message is a reply from extraterrestrials?

Implausible.	[0]
Not very plausible.	******* [7]
Somewhat plausible.	***** [5]
Very plausible.	[0]
(Unsure/guessing/lost/help!)	* [1]

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

"Do you think that Earth is the only planet with life?"

"Do you think the more advanced we get with technology, that eventually will figure out a way to find other life forms through our own tech, and if so how soon do you think that will be?"

"Do YOU legit think we're gonna find aliens out there someday? (Even if it's billions of years from now?)"

"Please talk about aliens."

FCI pre-test to post-test comparison

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

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

Physics 205A fall semester 2018 sections 70854, 70855 (matched-pairs only, N = 44)
<initial%>	= 30% ± 17%
<final%>	= 37% ± 18%
<g>	= 0.09 ± 0.18 (matched-pairs); 0.10 (class-wise)

The paired Student's t-test of the null hypothesis for Cuesta College FCI pre-test scores versus post-test scores results in p = 0.001 (t = –3.75, degrees of freedom = 43), thus there is a strongly statistically significant difference between Cuesta College FCI pre-test and post-test scores.

This Hake gain is comparable to previous semesters' paired results for algebra-based introductory physics at Cuesta College (0.11). (Previous semesters before 2017 were analyzed using unpaired results.)

Notable about this Physics 205A class at Cuesta College since fall semester 2017 is the absence of an embedded tutor (student teaching assistant circulating in class along with the instructor during open discussion and problem-solving sessions); otherwise as taught from fall semester 2014 onwards is the requirement that students read and answer questions on the textbook and lecture slides before coming to lecture (in a "flipped classroom"), instructor discussion in-class based on answering student questions and concerns submitted online previous to lecture, in-class problem-solving sessions ("lecture-tutorials," including ranking tasks, and/or a brief written explanation of a selected question submitted by each student every lecture).

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

Previous FCI results:

(Paired Student t-tests from 2017 onwards)

• Cuesta College, fall semester 2017 pre-test to post-test comparison.
  
  (Note only unpaired Student t-tests were run prior to 2017)
  
• Cuesta College versus UC-Davis, fall semester 2016 pre-test to post-test comparison.
  
• Cuesta College versus UC-Davis, fall semester 2015 pre-tests, and post-tests.
  
• Cuesta College versus UC-Davis, fall semester 2014 pre-tests, and post-tests.
  
• Cuesta College versus UC-Davis, fall semester 2013 pre-tests, and post-tests.
  
• Cuesta College versus UC-Davis, fall semester 2012 pre-tests, and post-tests.
  
• Cuesta College versus UC-Davis, fall semester 2011 pre-tests and post-tests.
  
• Cuesta College versus UC-Davis, fall semester 2009 pre-tests and post-tests.
  
• Cuesta College versus UC-Davis, spring semester 2009 pre-tests and post-tests.
  
• Cuesta College versus UC-Davis, fall semester 2008 pre-tests and post-tests.
• Cuesta College versus UC-Davis, spring semester 2008 pre-tests and post-tests.
• Cuesta College versus UC-Davis, fall semester 2007 pre-tests and post-tests.

Online reading assignment: standing waves

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 standing waves.


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.

"String tension and thickness determine the pitch of the note that the string creates when plucked."

"The frequency of the wave is set by the source. The speed of periodic waves along strings is set by the string tension and thickness. The fundamental frequency of a string depends on the wave speed v and length L."

"Different thicknesses of string vibrate at different fundamental frequencies when plucked. Thinner strings would have a higher fundamental frequency and thicker strings would have a lower fundamental frequency."

"Nodes are where there is no vibration at all and antinodes are the spaces where maximum vibration occurs. The distance between two nodes or antinodes of a standing wave is equal to half of its wavelength."

"Natural frequency is when resonance occurs. Guitar strings that are thicker resonate at a lower fundamental frequency than thinner strings. If a string were oscillated at twice its fundamental frequency, then it results in a pattern that creates a node in the center."

"All strings have their own fundamental frequency and you can have resonate frequencies by multiplying integers to the fundamental frequency."

"I didn't get to it yet."

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.

"The fundamental frequency equation and the resonant frequencies confused me some. How the fundamental frequency of a string depends on the wave speed v and length L."

"I'm still kind of confused on what a node actually is. Is it the portion that's completely still in the GIF animations? Or is it something completely different?"

"I was a little confused by fundamental frequency. I also found the questions kind of confusing."

"I feel like I understood this all pretty well."

(Assuming that their tensions are approximately equal), the __________ strings have a slower wave speed.

thicker.	******************************************* [43]
thinner.	[0]
(There is a tie.)	*** [3]
(Unsure/lost/guessing/help!)	[0]

After these same-length guitar strings are plucked (assuming that their tensions are approximately equal), the __________ strings vibrate at a lower fundamental frequency.

thicker.	********************************** [34]
thinner.	***** [5]
(There is a tie.)	******* [7]
(Unsure/lost/guessing/help!)	[0]

After the bass string is plucked, sliding a finger down to decrease its length would __________ the speed of waves along the string.

decrease.	***************** [17]
not change.	********* [9]
increase.	******************* [19]
(Unsure/lost/guessing/help!)	* [1]

After the bass string is plucked, sliding a finger down to decrease its length would __________ the fundamental frequency of the string.

decrease.	*********** [11]
not change.	******* [7]
increase.	*************************** [27]
(Unsure/lost/guessing/help!)	* [1]

For standing waves on a string, classify each of these parameters are being "independent" (able to be changed without affecting other independent parameters), or "dependent" (will be changed when independent values are changed).
(Only correct responses shown.)

Wave speed v: independent [39%]
String length L: independent. [59%]
Fundamental frequency f₁: dependent. [54%]

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

"Since fundamental frequency is equal to waves speed divided by 2·L, then wouldn't all of these parameters be dependent of each other because if the fundamental frequency f is changed then wave speed and or length would have to also be different values and vice versa?"

"I am currently learning how to play the guitar so this is cool to talk about!"

"I'm actually from Gig Harbor, Washington, which is on the other end of the Narrows Bridge from Tacoma. Galloping Gertie is a very familiar topic with me haha I have crossed the Narrows a thousand times. We learned about how they changed the structure of the bridge when they built the new one, and when you go to the Narrows Beach (Gig Harbor side) or Titlow Beach (Tacoma side) you can look up at the bottoms of the bridges and see all of the tresses. They had to make the bottom more open so there wouldn't be large solid surfaces to catch the wind the same way they did before. I remember when there was only one bridge that had traffic going both ways from the Harbor to Tacoma, but then there was so much traffic going back and forth that they built another one, and left the green one as east-to-west traffic (Tac to GH), and the new one as west-to-east traffic (GH to Tac). The tolls are still stupidly high, even though the bridge is paid off."

"I hope we go over all this in the lab on Monday better."

"How the length of the string effects the sound it makes."

"I enjoyed the partially/lightly flipped format of your class! Your class policies and procedures are very reasonable. I'm not sure what else to say to help improve your teaching methods; I believe you have done a wonderful job!"

Astronomy current events question: Arsia Mons cloud plume

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!)

Agustin Sánchez-Lavega, Daniela Tirsch, Brigitte Gondet, Dmitri Titov, and Markus Bauer, "Mars Express Keeps an Eye on Curious Cloud" (October 25, 2018)
esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_keeps_an_eye_on_curious_cloud

The European Space Agency's Mars Express spacecraft imaged __________ produced by atmospheric conditions near the Arsia Mons volcano.
(A) marsquakes.
(B) steam vents.
(C) thunderstorms.
(D) a cloud plume.
(E) a category 5 hurricane.

Correct answer: (D)

Student responses
Sections 70178, 70186
(A) : 2 students
(B) : 4 students
(C) : 2 students
(D) : 11 students
(E) : 1 student

Astronomy current events question: reflected sunlight from proposed "fake moon"

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!)

BBC News"Fake Moon: Could China Really Light Up t, he Night Sky?" (October 20, 2018)
bbc.com/news/world-asia-china-45910479

A private company has recently proposed launching several "huge mirrors" into orbit around Earth in order to:
(A) image exoplanets.
(B) deflect solar flares.
(C) illuminate a city at night.
(D) vaporize incoming asteroids.
(E) power the International Space Station.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 0 students
(B) : 3 students
(C) : 14 students
(D) : 1 student
(E) : 2 students

Astronomy current events question: slowest pulsar PSR J0250+5854

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!)

Jordan Kenny, "Slowest Ever Pulsar Star Discovered by PhD Student" (October 23, 2018)
manchester.ac.uk/discover/news/slowest-ever-pulsar-star-discovered-by-phd-student/

Observations from the Low-Frequency Array in the Netherlands revealed that PSR J0250+5854 is the __________ pulsar yet detected.
(A) coldest.
(B) farthest.
(C) smallest.
(D) slowest spinning.
(E) strongest magnetic.

Correct answer: (D)

Student responses
Sections 70178, 70186
(A) : 0 students
(B) : 3 students
(C) : 2 students
(D) : 11 students
(E) : 4 students