There are a few units that I'm interested in understanding a little better; mainly in understanding what they are based on. For example, 1 calorie is the energy to change the temperature of 1kg of water by 1C (IIRC). Here are the units I don't understand too well. reaumure - temperature torr - pressure bar - pressure I've already tried to get the info myself. For reaumure, I end up with a bunch of sites in French which doesn't help since I can't read French. Searching for the pressure ones lead me to a bunch of sciences questions/tests posted online.