• Question: What causes thunder?

    Asked by lisaloo to Claire, Kate, Matt, Rob, Sam on 24 Jun 2013.
    • Photo: Kate Husband

      Kate Husband answered on 24 Jun 2013:

      Thunder is caused by lightening heating the air which causes it to rapidly expand and hence create a sound wave which travels through the air to our ear. The sound waves travel much slower than the light (~330 metre per sec for sound and ~300 million metre per second for light!) which is why you see the lightening before you hear the thunder and why the difference in time between lightening and thunder can be used to measure how far away the storm is.

    • Photo: Matthew Pankhurst

      Matthew Pankhurst answered on 25 Jun 2013:

      Lightning super-heats air and it expands in a giant rush. This rush is like an air explosion – which sends a a shock wave though the air. The sound of rumbling thunder is the sound of huge numbers of air molecules bumping into each other. Cool huh?!

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