3 ms·
On that topic, does anyone know how these things work? http://www.amazon.co.uk/Magic-Gel-Reusable-Hand-Warmer/dp/B000MU4IJ2 http://www.amazon.co.uk/Magic-Gel-R
by Splines 14y ago
On that topic, does anyone know how these things work?
http://www.amazon.co.uk/Magic-Gel-Reusable-Hand-Warmer/dp/B000MU4IJ2 http://www.amazon.co.uk/Magic-Gel-Reusable-Hand-Warmer/dp/B0...
I've seen them in person and they're remarkable if you've never encountered them before.
- hexagonal 14y agoSodium Acetate. https://en.wikipedia.org/wiki/Sodium_acetate https://en.wikipedia.org/wiki/Sodium_acetate
- limmeau 14y agoI think there's a saturated solution of sodium acetate inside. The metal clickie causes the solution to crystallize, which happens to happen exothermically. (IANAchemist)
- vlisivka 14y agoCan I use sodium acetate to heat my energy passive home (which I will build soon) by heating it at day in Trombe wall and discharging it at night?
- xutopia 14y agoIt's most likely unwieldy. Sometimes you can cause the exothermic effect to occur without you wanting it by a vibration or shock.
- excuse-me 14y agoThey are a supersaturated Sodium acetate solution. Liquids give off energy when they freeze and take energy in when they melt. When you heat these and melt them they can stay stable as a saturated liquid until you create a small site for them to start freezing around - they then give off energy when they freeze. The 'clicker' is all that's required to localy concentrate it enough to form a single crystal seed to start the freezing