Reducing heat transfers – the human body
Heat energy is lost from the human body because body temperature is higher than room temperature.
However, there are ways that these losses can be reduced.
This is a Image made by detecting infrared radiation rather than visible light. Different colours are used to represent the different temperatures of the objects in the image. of a man, woman and child.
The white and red parts are the hottest and so are losing most heat. Orange and green represent medium temperatures, and blue and purple are the coldest parts.
It is easy to see that the heads of all three people are the hottest parts, followed by their torsos.
Their arms and legs show medium temperatures, while their hands and feet are among the coldest parts. It is in these places that we sometimes get frostbite in very cold conditions.
Hair on our head reduces heat loss because air is trapped between individual hairs.
To reduce heat transfers from our bodies, we can wear insulating clothing - such as gloves, scarves, hats and thermal socks - in cold weather.
The more layers we wear, the more air can be trapped and the warmer we will remain. Some clothes, such as wool, are excellent insulators, because they trap lots of air between individual fibres.