- Joule-Thomson Effect -

Although relatively easy to grasp for anyone in Physics, this discovery was key in understanding the relationships between pressure of gas and its temperature. The Joule-Thomson Effect shows that an insulated gas will lower its temperature as the pressure is decreased without doing any work. This was discovered by both Joule and Sir William Thomson, who would later be known as Sir Kelvin. This effect is also called the Joule-Kelvin Effect. This is the basis of how modern refrigeration techniques work.

Photo provided by: http://www.deutsches-museum.de/ausstell/dauer/physik/e_joule.htm