4C20.60: HAND WARMER

PURPOSE: To demonstrate the heat of fusion.

DESCRIPTION: A plastic bag contains a supersaturated solution of sodium acetate. When fusion is commenced by clicking a metal disc in the solution or by some other shock, the liquid quickly becomes solid, producing a large amount of heat.

SUGGESTIONS: Before re-using this gizmo, it must be boiled to put the heat back into the sodium acetate and change it back into a liquid.

REFERENCES:

EQUIPMENT: Hand warmer.

SETUP TIME: None.


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