This is BCE # 15. It is OK to use your textbook, but if you can answers the questions without it that is OK too.

I recommend you print out this page and bring it to class. Click here to show a set of five BCE15 student responses, randomly selected from all of the student responses thus far, in a new window.


, here are your responses to the BCE and the Expert's response.

1. Consider the two beakers containing water, both at the same initial temperature, say 25 degrees Celsius.

The beaker on the left has 25 mLs of water and the beaker on the right has 50 mLs of water. Both have the same initial temperature. If I add the same amount of heat to both beakers, using a bunsen burner, does the beaker on the right or the beaker on the left have the higher final temperature? Explain?

(When adding heat the final temperature depends on the amount of heat added and the amount of water present. In this case we are adding the same amount of heat to both beakers. So the beaker with the smaller amount of water will end up with the higher temperature. Was your intuition working?)

2. Consider the two beakers containing water, both at the same initial temperature, say 25 degrees Celsius.

If the final temperature of the water in both beakers is identical, is the greater amount of heat added to the beaker on the right or the beaker on the left? Explain.


(When adding heat the final temperature depends on the amount of heat added and the amount of water present. In this case there is different amounts of water in the beakers. The greater the mass the more heat that must be added to get the same temperature change. So we have to add more heat to the beaker on the right. Was your intuition working?)

3. Consider the two beakers containing water, both at the same initial temperature, say 25 degrees Celsius.

If twice as much heat is added to the beaker on the right compared to the beaker on the left, and the final temperature of the beaker on the right is lower than the beaker on the left, which beaker has more water? Explain.

( The beaker on the right will have more water. Again when adding heat the final temperature depends on the amount of heat added and the amount of water present. In this case there is different amounts of water in the beakers. The greater the mass the more heat that must be added to get the same temperature change. Adding twice as much heat and still having a lower temperature compared to the beaker on the left means there is much more water in the beaker on the right.)

4. Identical candles are used to add heat three different samples all having the same mass. The three samples are heated for a short period of time (so the wood does not catch on fire.) The three different substances are wood, glass and copper. Each is a cube. Each of the three substance is heated for the same amount of time with its candle. Based on your experience/intuition order the three substances as to its final temperature.

lowest final T..........highest final T

< <

(wood < glass < copper)


(When I've heated wood for a short period of time it does not appear to change its temperature by much. Glass gets hotter when it absorbs some heat and copper..a metal..gets even hotter than glass when exposed to heat. We'll talk about what is really going on here in class. But it has to do with specific heat of a substance. Another way to think about this problem relates to touching the sample of the material after it has absorbed some heat. We know that metals gets hot with a little amount of heat added. It takes a little more heat before a glass container feels hot, and wood takes even more. We might be able to pick up a piece of wood without fear of being burned ater some amount of heat has been added.)

5. Where would water fit in your order? Explain.

(Water will have even a lower final temperature than wood. Water has to absorb a lot of heat before it changes its temperature.)

6. Suppose you had had in view two samples of helium and you could see the atoms of helium at the atomic level. One of the samples of helium is at 25 degrees Celsius and the other is at 50 degrees Celsius. Assuming you were not told which sample was at which temperature, explain how you would identify which sample was at which temperature.

(The atoms of helium in sample at the higher temperature will, in general, be moving faster compared to the atoms of helium in the sample at the lower temperature.)

7. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

8. If there is one question you would like to have answered in lecture, what would that question be?