Heat engines and machines

2.1 Joule's experiment

When steam comes out of a pressure cooker, its energy is able to turn the valve. Part of the heat we have supplied to the water is converted into mechanical work. In the same way we know that if we rub two objects together, a form of mechanical work, we produce heat.

Thus, mechanical work and heat can be converted into each other. What is the conversion relation? The famous scientist J. Joule designed an experiment which enabled him to convert mechanical energy into thermal energy under controlled conditions to measure the equivalence between both forms of energy.

In the following visual, we simulate Joule's experiment in a very simplified way.

	Joule's experiment
	The first law of thermodynamics
	Conclusions