Question: how does heat move??

Nathan Quinlan answered on 31 Jan 2015:

Good question! Heat always moves from high temperature areas to cold areas. There are three main ways. Heat can move through solids – so if you touch a piece of cold metal, heat from your warm finger moved away into the metal. This is conduction. When a liquid or gas moves around, it brings heat energy with it – this is convection, and it’s why you feel colder on a windy day. Heat can also move in the form of light. Usually it’s invisible infrared light. Very hot objects, like the sun or the elements in a grill, give out heat as light you can see. When you feel the sun warming your skin, it’s the ordinary visible sunlight doing that. That’s thermal radiation.

Engineers who design anything involving heat have to understand these three modes. For example, your computer has fans that move cold air over the chips to keep them cool (convection). Satellites are exposed to strong sunlight on one side and extreme cold on the other – so it’s really tricky to keep their systems at a safe operating temperature. There’s no air up there, so it’s all conduction and radiation.