For each of these situations, answer questions 1-7 below.
A) Normal human body temperature is 37°C. Room temperature is more like 25°C. So unless it's really hot out, there is always a temperature difference between your body and its surroundings. What's going on?
B) You get too cold, and need to warm up. What happens?
C) You get too warm, and need to cool down. What happens?
D) Now answer parts A, B, and C for the ectothermic (i.e. what is popularly and inaccurately known as "cold-blooded") animal (e.g. reptile) of your choice!
1) What's happening? Explain what's going on qualitatively, and feel free to bring in outside knowledge.
2) What object or set of objects is the most useful for you to define as "the system"? (There are a large number of possible correct answers to this! But this is an important choice you must make.)
3) Draw a system schema for your system (which you can continue updating as you answer the rest of the questions).
4) During the process described, what is the change in the total energy of the system? (Positive, negative, or zero?)
5) Same question as 3, for the chemical energy in the system.
6) Same question as 3 for the thermal energy in the system.
7) Does any energy enter or leave the system? If so, by what process (heat, work, etc.)?
Comments (1)
Ben Dreyfus said
at 12:53 pm on Dec 28, 2012
Drat! We added part 3 this year, but didn't update the numbering in parts 5 and 6 (it should now have said "same question as 4"). No wonder the students were confused! They were trying to make separate system schemas for the thermal energy and for the chemical energy! I don't even know what that means! I'm creating a "2013 revision" right now and fixing this.
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