A seed crystal can be dropped into a saturated solution of sodium acetate. The solution will suddenly crystallize and turn to solid. Alternately, the solution may be slowly poured out onto a seed ...

A reusable hot pack made of a supersaturated sodium acetate solution that crystallizes spontaneously once triggered by a metal piece releases heat. A balloon filled with hydrogen gas also releases ...

When it is exposed to air, the iron begins to rust. This rusting process produces heat. The second contains a solution of the chemical sodium acetate and a small metal disc. When the disc is bent, ...

When a metal disc in the pouch is flexed, the sodium acetate nucleates on the disc, eventually crystallizing the entire pack and becoming hot. The pack is designed to fit in the hand and would not be ...