Chapter 13, Problem 96AE

One of the important ideas of thermodynamics is that energy can be transferred in the form of heat or work. Imagine that you lived 180 years ago when the relationships between heat and work were not well understood. You have formulated a hypothesis that work can be converted to heat with the same amount of work always generating the same amount of heat. To test this idea, you have designed an experiment using a device in which a falling weight is connected through pulleys to a shaft with an attached paddle wheel that is immersed in water. This is actually a classic experiment performed by James Joule in the 1840s. You can see various images of Joule's apparatus by searching the Internet for "Joule experiment images."

1. Using this device, what measurements would you need to make to test your hypothesis?
2. What equations would you use in analyzing your experiment?
3. Do you think you could obtain a reasonable result from a single experiment? Why or why not?
4. In what way could the precision of your instruments affect the conclusions that you make?
5. List ways that you could modify the equipment to improve the data you obtain if you were performing this experiment today instead of 180 years ago.
6. Give an example of how you could demonstrate the relationship between heat and a form of energy other than mechanical work.