What is the relationship between supersaturation and the hand warmer in figure 16?

Supersaturation refers to a solution that contains more solute than can ordinarily dissolve at a given temperature, creating a state of instability. In the context of a hand warmer, when a supersaturated solution is triggered (often by a physical action like flexing a metal disk), it rapidly crystallizes, releasing heat in the process. This exothermic reaction transforms the liquid into solid crystals, providing warmth. The relationship highlights how supersaturation can be harnessed for practical applications like hand warmers.