The story
Named after James Prescott Joule and William Thomson, 1st Baron Kelvin, who discovered it in 1852.
Etymology from Wiktionary, CC BY-SA 4.0.
Joule-Thomson effect
Today it means: The temperature change of a real gas or liquid (as differentiated from an ideal gas) when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment. Full definition →