• Question: If water is clear, then why is snow white ?

    Asked by nmaciag21 to Amy, Karen, Sarah, Vijay, Will on 18 Jun 2012. This question was also asked by caitlin7, coolperson, thedonishscienceexperiment115, meg123, mariannaxox, ciaragrimesxox.
    • Photo: Amy Birch

      Amy Birch answered on 18 Jun 2012:

      Hi nmaciag21,
      Great question!
      Light is made up of lots of different colours and the colour of objects depends upon which colour in light is absorbed by an object it hits and which colour is reflected back into our eyes. In water, all the different colours of light are absorbed so there is not much light to be reflected back into our eyes. Have you noticed that deeper water is blue? This is because as light travelled through water, more of the red in light is absorbed and more blue in light is reflected back to our eyes and this is what we see.
      Snow is lots of tiny ice crystals all bunched together so when light hits the ice crystals bounces off them in a different direction which makes it hit another ice crystal, which makes it bounce off in another direction and so on. The light is eventually bounced back out of the crystals and into our eyes as white.
      Hope this answers your question 🙂

    • Photo: Will Reynolds

      Will Reynolds answered on 18 Jun 2012:

      Hi nmaciag. Like Amy explains Ice is usually white, but sometimes it can be clear too. When water freezes the molecules arrange themselves into cubes and stack together, due to something called hydrogen bonding. The middle of these cubes is big enough to trap air molecules. If water freezes quickly, like in freezers and clouds, it traps air inside the ice and and light is refracted between the ice crystal and the air so you cant see through it and it appears white. But if ice forms slowly, like in stalagmites and stalagtiles in ice caves, then air has enough time to escape and is not trapped inside. In this case light can pass all the way through the ice without being refracted so you can see through it and it appears clear.

    • Photo: Sarah Martin

      Sarah Martin answered on 18 Jun 2012:

      Hi nmaciag21! We can see straight through water, because light can travel straight through water. Snow on the other hand consists of lots of little ice crystals, each of which will reflect light – all added up, when we look at snow, we just see light bouncing back from the surface!
      🙂 Sarah

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