• Question: What causes a rainbow?

    Asked by shannonlouise123 to James, Marcus, Martin, Rob, Suzanne on 19 Mar 2012.
    • Photo: James Boone

      James Boone answered on 19 Mar 2012:

      It is caused by a phenomenon called refraction. White light from the sun is made up of lots of individual colours (frequencies). When white light passes through water drops in the air, these different frequencies are bent by different amounts, which causes the beam of white light to split up into its individual components. It’s these individual colours that spread out causing a rainbow to appear in the sky.

    • Photo: Robert Thompson

      Robert Thompson answered on 19 Mar 2012:

      Yes again James got the right answer in before me. It’s pretty cool that white light is actually just a mix of all the colours of the rainbow. If you’ve ever seen a prism work it’s the same effect, a band called Pink Floyd had a famous album cover showing a prism doing this.


    • Photo: Marcus Gallagher-Jones

      Marcus Gallagher-Jones answered on 20 Mar 2012:

      Haha too late. Yes this is probablly one of the earliest physics experiments I remember doing.

    • Photo: Suzanne McEndoo

      Suzanne McEndoo answered on 21 Mar 2012:

      Yup, the guys have already covered it. You can also get lots of different types of rainbow depending on light conditions. You can get a double rainbow from a double reflection in the raindrop, and because the light has been bounced twice, the colours are in a different order.

    • Photo: Martin Zaltz Austwick

      Martin Zaltz Austwick answered on 22 Mar 2012:

      You can make your own rainbow with a sunny day and a hosepipe! Although that’s a bit of a waste of water, but if you’re washing a car or something – go for it.