Hot and Cold: All About Temperature

What is temperature?

Temperature tells us how hot or cold something is.

A cup of soup can be hot. An ice cube is cold. A warm bath is somewhere in between. Temperature is the word for all of this.

Hot things and cold things

Look around. Some things are hot and some are cold.

• Hot: the sun, soup, a warm radiator, a cup of cocoa.
• Cold: ice cubes, snow, a cold drink, the inside of a fridge.

Some things feel just right — not too hot and not too cold. Like a sunny day in spring!

How we measure temperature

We use a tool called a thermometer to measure temperature.

A thermometer can tell you exactly how hot or cold something is. Doctors use one to check if you have a fever. A grown-up might use one to see how warm the oven is.

Heat likes to move

Heat is a kind of energy. You can learn more in our lesson on forms of energy.

Heat always moves from the hot thing to the cold thing.

• A warm hand can melt a cold ice cube.
• Hot soup gets cooler as the heat leaves it.
• A cold drink gets warmer if you leave it out.

That is why ice cream melts on a warm day!

Try it yourself! 🧊

Ask a grown-up to help. You will need three bowls and water.

1. Fill one bowl with cool water (not freezing).
2. Fill one bowl with warm water (not hot).
3. Leave one bowl empty for now.
4. Dip one finger in the cool water and one finger in the warm water. Feel the difference!
5. Now put both fingers in a bowl of room-temperature water. One feels warmer, one feels cooler — but it is the same water!

This shows how your skin feels hot and cold.

Stay safe: Never touch very hot water, stoves, or ovens. Always ask a grown-up first.