| 12 EUR | (15.00 EUR incl. vat) |
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Delivery - immediate
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Study heat conduction, energy conversion and chemical reactions.
The hand warmer contains a supersaturated solution of water and sodium acetate. When the small metal disc in the pack is bent, a small amount of energy is supplied to the solution. This small amount of energy is sufficient to start a chemical reaction where the solution changes from liquid to solid form during an exothermic reaction. During the time the process is taking place heat is released which the hand warmer then emits over a long period.
Boiling the hand warmer causes the solution to return to liquid form and the hand warmer can be used again and again.
Material: Sodium acetate solution wrapped in plastic.
Temperature: approx. 50°C on activation, approx. 30°C after two hours at room temperature.
Dimensions: 10x10 cm.
Weight: approx. 150 g.
Manual in English included.
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