Heat. What type of body responds

1986/06/01 Aizpurua Sarasola, Joxerra Iturria: Elhuyar aldizkaria

• Fisika

The term heat is intimately linked to our life. It is known that not all bodies respond equally to heat. Although the causes of the experiences discussed below have not been theoretically analyzed, you should note that all these trials are based on physical laws.

We form with a cardboard a box like a box of pots. Once full of water, we hang the box with some threads. Then the box is heated with a candle, in which the flame only affects the area where the water is located. After a few minutes of waiting the water begins to boil, keeping the whole box.

Although it is up to you to explain the reason for this phenomenon, we give you the idea that the thermal conductivity of the water is much greater than that of the cardboard, although the flame hits the box, the water absorbs almost all the heat. If you don't get along with the cardboard box, you can test with an egg crust.

If you can go to the snow you can do a very simple rehearsal. On a sunny day, place two scarves on the snow, one black and one white. After a while of waiting place one hand on the white scarf and the other on the black. You have clearly noticed that the white scarf is cooler than the black one. Simple essay, right?. But we can conclude that not all colors absorb the sun's rays equally. So now you will understand the reason that most houses in the Andalusian villages are whitish. If they were black, they would absorb most of the sun's rays and of course there would be no life inside the houses because of the heat that would accumulate. Once you read these lines, you will find it easy to answer the following question:

"Why do skiers get so black in a short time?"