20131201

Online reading assignment: internal energy

Physics 205A, fall semester 2013
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 a presentation on internal energy.

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.
"Internal energy is really interesting because it's something I focused on this past June once I reached the top of Mt. Lassen in a t-shirt and shorts, I had to put my body in position with my arms crossed across my chest to keep my internal temperature from dropping."

"This reminds me of chemistry."

"A 'Calorie' as I knew it in my daily life is in fact 1,000 calories."

"I thought the balance of heat equation was interesting. And the fact that heat always flows from hot to cold. That's why touching a hot pan hurts."

"Internal (thermal) energy depends on the product of mass, specific heat capacity and temperature."

"While it was also the most confusing part of this section, the relationship between heat and temperature is interesting because of how it kind of sums up physics in a way. It's very relatable, but with just enough of a twist to catch you off-guard and force you to reconsider what you know."

"I thought it was interesting that two objects in thermal equilibrium might not have the same internal energy because I would expect that they would be 'equal.'"

"I'm used to the chemistry viewpoint, so it's interesting to see specific heat described from a physics perspective."

"I found it interesting that the heat and heat capacity are different than what we would instinctively expect them to be. Heat is not defined as hotness nor is heat capacity the capacity to hold heat within the system."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"It took a while to shake off the traditional idea that heat and temperature are interconnected, but aside from that and initially struggling to find the symbol for heat (which can be chalked up to user error), nothing was really all that confusing in this section.."

"I felt this section made it easy to understand heat and specific heat."

"I could not find the symbol for heat."

"I'm confused about the difference between C and c. They are describing them as different, but I don't see how."

What is the symbol for heat, and what SI units does it have?
"T, kelvins."

"Q, joules."

What is the symbol for heat capacity, and what SI units does it have?
"T, kelvins."

"C, J/K."

What is the symbol for specific heat capacity, and what SI units does it have?
"Isn't this the same as heat capacity? How is it different?"

"c, J/(kg·K)."

As an object is heated up, its __________ will increase.
internal energy.  *** [3]
temperature.  ** [2]
(Both of the above choices.)  *************************************************** [51]
(Neither of the above choices.)  [0]
(Unsure/guessing/lost/help!)  * [1]

Two objects that are brought into contact with each other will reach thermal equilibrium when they have the same:
internal energy.  *********** [11]
temperature.  ******************************** [32]
(Both of the above choices.)  *********** [11]
(Neither of the above choices.)  [0]
(Unsure/guessing/lost/help!)  *** [3]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"That balrog joke was some seriously classic P-dog material. Well-played." (You're welcome.)

"I noticed in the syllabus that it says that we have eight quizzes, but I only see that we have seven quizzes. Are we still dropping three or two quizzes and/or keep our top five?" ("Quiz 8" is credit for taking the in-class education research surveys, during the last week of class.)

"Why do we use C in chemistry to represent specific heat and only c in physics?" (Upper-case C is (total) heat capacity, while lower-case c is (mass-)specific heat capacity.)

"I just want to thank you for making the problems in this class fun and relative to everyday circumstances."

"That last midterm was hard and I had a really difficult time studying for it. I did not feel prepared."

"Do we turn in Lab 13 on the day of our final?" (You'll turn in the last lab on the last day of lab, before you leave.)

"Will there be any more extra-credit offered?" (The Magic 8-Ball™ in my office says, "outlook good.")

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