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J. Perelman
"Entertaining physics". Book 1.
Chapter 6. Thermal phenomena

WARM A COAT?

What would you say if you were to assure that the coat is not warm? You would have thought, of course, that you are joking. And if you have to prove this assertion on the number of experiments? Do such experiences. Note, shows how the thermometer, and cover it in fur coat. After a few hours remove. You make sure that it has not heated up even a quarter of a degree: as shown before, so many shows now. Here is the proof that the coat is not warm. You could suspect that coats even cold. Take two bladder with ice; one cover in a fur coat, another leave the room unlocked. When the ice in the second bubble will melt, expand coat: you'll see that here he almost didn't start to melt. So, the coat is not only warmed the ice, but it seems as if it were chilled him, slowing melting!

What can you argue? How to refute these arguments? No. Coats really not warm, if the word “warm” to understand the message of warmth. The lamp warms, the oven heats, the human body warm because all these items are sources of heat. But the coat in this sense does not warm. It is their heat does not, and is only hindered by the warmth of our body to get away from him. That's why a warm-blooded animal, the body of which is itself a source of heat, will feel the coat is warmer than without it. But the thermometer does not generate its own heat, and its temperature will not change from what we salutem in his coat. Ice wrapped in a fur coat, longer retains its low temperature, because the coat is a very bad conductor of heat slows down the access of heat from the outside, from the room air.

In the same sense as the coat, the snow warms the earth; being, like all of the powder bodies, a poor conductor of heat, it prevents the warmth to leave covered them with soil. In the soil, protected by a layer of snow, the thermometer shows often at least ten degrees higher than in the soil is not covered with snow.

So, the question, warms us fur coat, you have to answer that coat only helps us to warm ourselves. It would be better to say that we gray coat, and it is not us.

Entertaining physics J. Perelman

 




System Orphus

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