• Question: Why is the sky blue?

    Asked by Ruben to Lisa, Mark, Rachel, Sammie, Stephen, Tim on 13 Mar 2018.
    • Photo: Sammie Buzzard

      Sammie Buzzard answered on 13 Mar 2018:

      Sunlight is scattered in all directions when it reachers the Earth’s atmosphere by the gases and particles in the air. Blue is scattered more than other colors because it travels as shorter, smaller waves which is why we see the sky as blue (although living in London it’s easy to forget what a blue sky looks like!)

    • Photo: Mark Mirmelstein

      Mark Mirmelstein answered on 13 Mar 2018:

      The scattering Sammie mentioned is called the Rayleigh scattering, and indeed it means that shorter wavelengths are scattered more. So you can also ask yourself why aren’t the sky purple! The answer for that is probably that our eyesight is more sensitive to green light, because this is the dominant light we get from the sun, so our eyes make us see the sky blue because blue is closer to green, but in fact the sky is purple 🙂

    • Photo: Tim Duckenfield

      Tim Duckenfield answered on 14 Mar 2018:

      Exactly as the others have said, it is because the air prefers to look blue! You will notice during sunrise and sunset, the sky turns more red or pink – this is because the light has to travel through lots more air to reach our eyes (think about the angles). It goes through so much air, that all the blue light has been taken by the air, leaving only the red light!

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