• Question: why is ice clear and snow white?

    Asked by msummers to Amy, Drew, Julia, Kimberley, Sara on 22 Jun 2011. This question was also asked by jackietang, jknight.
    • Photo: Drew Rae

      Drew Rae answered on 17 Jun 2011:

      Hi Guys. Ice is a crystal structure – everything lines up, so it’s easier for light to pass through. Snow are crystals, but there are lots of individual crystals so they don’t line up. That’s a little oversimplified, but it’s the general idea.

    • Photo: Kimberley Bryon

      Kimberley Bryon answered on 17 Jun 2011:

      Snow and ice are both made of water molecules.

      As Drew said, the water molecules in ice are arranged in a regular crystal structure. This Lets light pass through without it being scattered, making it appear clear. Snow flakes although being made of water molecules also arranged in crystals, are very irregularly shaped and therefore the light passing through them is scattered in different directions as it passes through making them appear white.

    • Photo: Julia Griffen

      Julia Griffen answered on 18 Jun 2011:

      These guys have got it.. just to add ice is a highly ordered crystal structure due to hydrogen bonding..which also makes it float… google it if interested.. super question tho!

    • Photo: Amy MacQueen

      Amy MacQueen answered on 21 Jun 2011:

      Hey peeps!

      It’s to do with the particle size – the crystals in snow are much bigger and there are many air bubbles so all of the light which hits is bounces off the crystals and is reflected. Since this happens across the spectrum the snow appears white. Ice is made up almost entirely of crystals without the air bubbles so the light can penetrate much further into it.

    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 22 Jun 2011:

      Hello again msummers, jknight and jackietang!!

      The others have got it right! Snow is made of ice crystals mixed with air molecules. The air gaps between crystals, along with the crystals’ beautiful and complex shapes, bounce the light beams around so much that all the wavelengths eventually get reflected out, giving snow a white color (white light is what we see as the sum of all the other visible wavelengths).

      On the contrary, ice doesn’t have a lot of air. This allows light to pass through the highly ordered structure of ice with minimal reflection. Sometimes ice can appear blue however, like in glaciers, because it is so thick it absorbs the longer red wavelengths!