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πŸŒ‹ Planet Earth β›ˆοΈ Weather and climate

Thunder

Thunder is a sound caused by lightning. Lightning heats the nearby air and makes it expand; the hot expanding air hits the cold air, making the sound waves we hear as thunder. Thunder's different sounds come from different parts of the lightning bolt: the main channel makes a loud crash, and the branches make sharp cracks.
Thunder is a sound caused by lightning. Lightning heats the nearby air and makes it expand; the hot expanding air hits the cold air, making the sound waves we hear as thunder. Thunder's different sounds come from different parts of the lightning bolt: the main channel makes a loud crash, and the branches make sharp cracks.

πŸ“– In short

Thunder is the loud sound we hear after lightning: boom! It happens when lightning suddenly heats the air around it to a very high temperature, so the air expands very fast like an explosion and makes this rumbling noise.

🀩 Did you know?

  • Light travels at about 300 thousand kilometers a second.
  • Sound travels through air at about 340 meters a second.
  • Thunder can be heard up to about 15 kilometers away.
  • There's no thunder without lightning.

πŸ”Ž Find out more

🌟 Why do we see lightning before thunder?

Lightning and thunder happen at the same moment, but light travels much, much faster than sound, so we see the lightning first and hear the thunder afterwards.

πŸ” How far away is the storm?

When you see lightning, count the seconds until you hear thunder, then divide by three, and you'll know roughly how many kilometers away the storm is!

πŸ’‘ A long rumble

Sometimes we hear thunder as a long rolling rumble, because lightning is very long, so the sound from its different parts reaches us at different times and bounces off mountains and clouds.

🎯 If you hear thunder

If you can hear thunder, you're close enough for lightning to reach you. So go somewhere safe right away, and keep away from water and open spaces.

πŸ“Έ More pictures

Thunder is a sound caused by lightning. Lightning heats the nearby air and makes it expand; the hot expanding air hits the cold air, making the sound waves we hear as thunder. Thunder's different sounds come from different parts of the lightning bolt: the main channel makes a loud crash, and the branches make sharp cracks.
Thunder is a sound caused by lightning. Lightning heats the nearby air and makes it expand; the hot expanding air hits the cold air, making the sound waves we hear as thunder. Thunder's different sounds come from different parts of the lightning bolt: the main channel makes a loud crash, and the branches make sharp cracks.

🧩 Test yourself

1 Why do we see lightning before we hear thunder?

2 What causes the sound of thunder?

3 Light travels at about ?? thousand kilometers a second.

4 Which picture shows β€œThunder”?

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