Warm coffee

How to warm some coffee during a snow storm in the mountains? It's simple! Push in the bottom of the container and shake for 40 seconds. The coffee is ready! The commodity is 2 Euros, but who wouldn't spend it to get warm during a snow storm? And there is a different treat for summer: frozen coffee. For the service manual read above!

In fact, the container has a double bottom. A cooling or heating mixture is placed in the bottom part of the container. The coffee is in the top part. To heat something we use a reaction of calcium chloride with water, and to cool something we dissolve sodium thiosulfate (photographic fixer) in water.

But why do certain materials heat when they dissolve or melt, e.g. acids, and others cool? It has yet to be determined. Experienced chemists say it just happens that way.