Question: What happens when you melt and freeze salts?

Emily Goddard answered on 9 Mar 2020: last edited 9 Mar 2020 9:20 pm

It’s just like when you melt and freeze water or anything else — when you melt a salt it takes in heat energy to relax the bonds and turn into a liquid, and when you freeze it it becomes solid again.

The thing that’s important in my work is that when you melt a salt it takes in a lot of energy, and this energy can then be released as heat when you freeze it again — think of the handwarmers with the clicky disc in them.