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πŸ§ͺ Science πŸ’‘ Light and sound

Light

Light

πŸ“– In short

Light is what lets us see the world around us. It falls on things and bounces back into our eyes, so we see them. Without light everything is dark. The biggest source of light is the Sun, and there are also lamps, fire and stars.

🀩 Did you know?

  • The speed of light in a vacuum is about 299792 kilometers per second.
  • Sunlight takes about 8 minutes to reach the Earth.
  • In 1905 Einstein discovered that light comes in tiny packets of energy.
  • Some animals make their own light, like fireflies.

πŸ”Ž Find out more

🌟 The fastest thing in the universe

Light is the fastest thing in the universe, traveling about 300 thousand kilometers a second! It could go around the Earth seven and a half times in one second.

πŸ” It travels straight

Light travels in straight lines. So when something gets in its way, a shadow forms behind it. And light can't bend around corners.

πŸ’‘ Reflection and refraction

When light hits a mirror it bounces off, and that's reflection. When it goes into water or glass it bends, and that's refraction, which is why a pencil in a glass of water looks broken.

🎯 Ibn al-Haytham

People used to think the eye sent out rays in order to see. Then the scientist Ibn al-Haytham proved by experiment that light comes from objects to the eye, and he became one of the greatest scientists of light.

πŸ“Έ More pictures

Light

🧩 Test yourself

1 What is the fastest thing in the universe?

2 Why does a pencil look broken in a glass of water?

3 The speed of light in a vacuum is about ?? kilometers per second.

4 Which picture shows β€œLight”?

πŸ§ͺ Discover more

πŸ“· Picture sources: Wikimedia Commons