HOW HEAT WORKS
If you pick up a water bottle or open a metal gate on a cold day, you lose a lot of heat quickly. That’s called conduction; where cold things pull heat away on contact. We most often feel that through the soles of our feet in cold boots or if we sit on a cold rock.
More crucial to outdoor clothing are the other three types of heat transfer: radiation, convection and evaporation. Your entire body is constantly
radiating heat. You are literally a radiator giving off waves of energy which will warm the air and clothing around you. Then comes convection, which is radiation’s partner in crime. As you heat the air molecules near your skin, they move and are replaced by unheated molecules. If there’s air-flow over your skin, this happens more quickly and you lose much more heat – that’s called windchill. And lastly there’s our old friend
evaporation – the one which sweating relies on – which is happening all the time. The basic process of liquid returning to its gaseous state. Even sitting there reading Country Walking you’ll be sweating a little bit.