Latent Heat of Fusion, Specific Heat, & Climate Change

I want to start by explaining a concept from physics known as latent heat, specifically the latent heat of fusion. Latent heat is the energy involved when materials change their phase, meaning they go from one form of a solid, liquid, or gas to another. The latent heat of fusion is specifically the amount of energy in the form of heat is absorbed by a material when a solid changes to a liquid. In order to melt 1 gram of ice into water, it takes 334 Joules of energy. There is no temperature change during this transition – the 0°C ice becomes 0°C water after absorbing all of that heat. Keep in mind it takes about 4.2 Joules to heat a gram of water by 1C°. It is pretty easy to see that it takes nearly 80 times the energy to melt water as it does to then heat it by 1C°. Or to put it another way, the energy it takes to melt ice could heat a mass equivalent of water by nearly 80C°.

The other concept important to note it one of specific heat and the related heat capacity. Specific heat is the concept of how much energy it takes to heat something (or how much energy it gives off in cooling). As mentioned previously, it takes about 4.2 Joules to heat just a single gram of water by 1C°. For comparison of the mass, a tablespoon of water is about 15 grams. So it takes 63 Joules to heat a tablespoon of water by 1C°. To give an idea of how that energy compares, it takes about 0.7 Joules to heat up a gram of sand 1C°, steel about 0.47 Joules, and gold about 0.13 Joules. Continue reading