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The Challenge: Make Ice



What liquids could we use as a coolant?

There are a number of possibilities but it depends on two key properties: boiling point and latent heat of vaporization.

The latent heat of vaporization of a liquid is the amount of energy in joules required to turn one gram of the liquid into a vapor. When you get out of the shower or bath and feel cold it is because for every gram (.03 oz.) of water that evaporates from your skin 2264 joules (539 calories) of energy are being used to evaporate that gram of water. The energy is taken in the form of heat from you and therefore you feel cold.

Boiling temperature and latent heat of vaporization of some liquids:

Liquid at atmospheric pressure Boiling Temperature oC (oF) Approximate Latent Heat of Vaporization, (joules/gram)
Ether (C2H5)2O 34.5 (94.1) 378 ( 90 calories)
Acetone (CH3COCH3) 56.2 (133.16) 987 (235 calories)
Methanol (CH3OH) 64.5 (148.1) 1008 (240 calories)
Ethanol (C2H5OH) 78.3 (172.94) 848 (202 calories)
Water (H2O) 100 (212) 2264 (539 calories)