Heat

📖 In short

Heat is an important kind of energy. We feel it in the sun's warmth, in hot food and in the fire of a heater. Thanks to heat we cook, keep warm and make things. Heat always moves from a hot thing to a cold thing.

🤩 Did you know?

A lot of heat must be taken out of water for it to turn to ice.
Metals conduct heat fast, which is why they feel cold to touch.
A thermos flask keeps drinks hot or cold because it stops heat moving.
The German scientist Mayer published his research on heat and energy in 1842.

🔎 Find out more

🌟 What is heat?

Everything is made of tiny atoms that move and jiggle. The hotter something is, the faster its atoms move. Heat is this movement!

🔍 How does it move?

Heat moves in three ways: by touch, like a metal spoon warming up in tea; by the movement of air and water, like hot air rising; and by rays, like the sun's warmth reaching us through space.

💡 Expansion

Most things get bigger when they heat up and shrink when they cool down. That's why engineers leave small gaps in bridges and railway tracks.

🎯 Insulators

Some materials stop heat moving, like wool, wood, plastic and trapped air. That's why we wear wool in winter and hold pots with a cloth oven glove.

🧩 Test yourself

1 Which way does heat move?

2 Why do we wear wool in winter?

3 Which picture shows “Heat”?

🧪 Discover more

📷 Picture sources: Wikimedia Commons

alex lines from brooklyn, usa · CC BY-SA 2.0