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The thermal conduction in everyday life


Since Prehistory, humans have been observing nature and learning from it.

Early humans realized that some animals that resist cold well are coated with hair.

This is the case with bears and reindeer. This observation must have inspired prehistoric humans to use animal skins to protect themselves from the cold. We currently wear appropriate clothing for this: the warm clothing.

The clothes we wear, the animal hair and the fat layer of some of them have under the skin are good thermal insulators, which make it difficult for the body to escape heat to the cold environment.

Bird feathers also play a role in making heat loss difficult for the environment. Between the feathers, a little air is trapped, which is a good thermal insulator and further reduces heat loss. Styrofoam, which is used to make insulating coolers, uses exactly the same principle. It is nothing more than a type of plastic (called polystyrene) made to contain many tiny air bubbles within itself. These bubbles are so small that we can't see them, but it's their presence that makes Styrofoam cute and makes it a good thermal insulator.

Ice is also, strangely enough, a good thermal insulator. The Eskimos may have realized that the ice that forms on the surface of the lakes prevents contact of the water below it with cold air, that is, it acts as a thermal insulator, so that water does not freeze. Possibly from there came the inspiration to make the igloos, ice constructions whose interior is warmer than the external environment.

In the kitchen we find numerous examples of heat exchange by driving. By placing ice in a soda glass, for example, the heat exchange warms the ice and cools the drink.

Using wooden or plastic spoons, we can mix the boiling food without burning our hands. Metal spoons, on the other hand, spread heat quickly, and the handle heats up, offering a risk of burns.

Aluminum and stainless steel are metals used in pans, as they ensure rapid heat transfer from flame to food. Already the handle of many pans is wood or bakelite, which are insulating materials that prevent burns on those who handle them.

Glass and ceramics, unlike metals, are not good conductors of heat. Glass or ceramic pots and pans require more time to transfer heat to the environment. That is why, to maintain the temperature of the food, it is ideal to serve in ceramic vessels.