Create liquid heat!
Experiment with creating your own heat pack. Sodium Acetate Trihydrate is the active ingredient commonly found in heating pads and hand warmers.
When Sodium Acetate Trihydrate crystals are heated to the point of melting and then they are allowed to cool, the resulting solution becomes supersaturated. This solution is capable of cooling to room temperature without forming crystals. When clicking on a metal disc in the crystal solution, a nucleation center is formed which causes the solution to crystallize into solid Sodium Acetate Trihydrate again thus giving off heat. Unlike some other types of heat packs, sodium acetate heat packs can be easily recharged by boiling until all crystals are dissolved again.
500 grams of Sodium Acetate Trihydrate comes in a plastic container.