Hand Warmers

Hand warmers are specifically designed to keep your hands warm in the Winter. This is done by the chemicals in the liquid having an exothermic reaction. An exothermic reaction is a reaction that emits heat. This happens when a metal disk being snapped/ clicked, which sends a wave creating a chemical reaction in the liquid salt solution. This then crystallizes, turning the state to a solid. The solid then transfers the heat through conduction, when held to make your hands nice and toasty! It can reach up to 130F for 30 minutes! Some people put hand warmers in gloves as gloves are good insulators of the heat. This would reduce the amount of heat able to escape, as heat travels from hot to cold.

Even though black would be the better colour for the handwarmers, because black is a good emitter of heat, companies make them in pretty shapes and colours for marketing puropses.

A variety of coloured handwarmers.
A variety of coloured handwarmers.

Hand warmers aren't disposable, they are reusable. Once the hand warmer has cooled down, you are able to boil the handwarmer. The salt redissolves in the pack, creating a clear solution, an endothermic ( opposite to exothermic ) reaction. It absorbs heat instead of emmiting it. Once this has also cooled down, you can snap the disk and use again! Voila!

Here is a youbtube clip shwoing someone activating a hand warmer:

http://www.youtube.com/watch?v=YfTln_hHFDQ&feature=related


Tayla Morhall & Elizabeth O'Brien