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Physics Biology
age: 9 – 15

Cold metal?

Why does wool feel warm and metal cold – even though both are at the same temperature?

Learning objective

Understanding the impact of heat transfer on our temperature perception.

Coins or other metal objects
Paper or wool

At the beginning of the lesson, let each student put a coin on the table, so that it can acquire room temperature.

Student Task

For a few seconds, hold a piece of paper (or wool) against the back of your hand. Then repeat this with a coin instead of the paper.

1. Why does the coin feel colder than the paper?


Except in very hot regions or on hot summer days, the human body is warmer than its environment. When touching a metal object at room temperature, the metal will quickly absorb heat from the body and make the skin feel colder. Paper or wool feel warmer, because they absorb the body heat at a slower rate. For the same reason, floor tiles feel colder than carpet.

Materials with a high thermal conductivity, like metals, not only absorb heat more quickly, but also dissipate it faster into the environment. Wool, in contrast, prevents the loss of body heat through wind. That is why it is used in clothing to protect from cold.