• Question: How fast is the speed of electricity and light?

    Asked by ishyk123 to Ashley, Bernard, Carsten, MariaMagdalena, Monique on 17 Nov 2015.
    • Photo: Monique Henson

      Monique Henson answered on 17 Nov 2015:

      It depends on what they’re travelling through. The fastest light can travel is the speed it travels through a vacuum at. That’s 299,792,458 metres per second, which is pretty quick. It turns out that that’s the fastest anything can travel – so we tend to think of it as a universal speed limit.

      Light does slow down in different materials though. For example in water it travels at around 225,000,000 metres per second. Some materials slow light down quite a lot. In the late 90s, scientists from the University of Harvard managed to find a material in which light travelled at only 17 metres per second. You can read more about that here.

      I’m not sure about electricity at the moment. Let me have a think and I’ll get back to you!

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