Why is ocean blu and glaciers white?

Question

Why is ice white?

Answer 1

Here, I will settle this.  What water does to light is pretty much the same thing air does, ie diffusion through Rayleigh scattering.  This is why in small amounts, water is clear, and in large amounts it appears blue or blue-green (depending on the contents).  But the surface of water reflects all colors of light.  This is why a pond or other flat surface of water makes an exact copy of whatever it's reflecting.  This has a lot to do with why the ocean appears blue.  If you notice, on a cloudy day, the ocean looks a lot grayer.  This is because it's no longer reflecting the blue sky.  Also, water does absorb red light before other colors but this isn't the main contributing factor to the blueness of the ocean, and it's mostly due to other things (mostly organic chemicals) in the water.

Now, keep in mind that the SURFACE of water reflects ALL colors.  Ice is full of tiny air bubbles and other imperfections.  Each air bubble has a surface.  So ice, in general, has a whole lot of surface area all throughout it.  Especially glacier ice.  So light gets reflected and re-reflected (ie, diffused) through ice.  Also, glaciers are usually covered with snow.  The snow (which is crystallized water and therefore has lots of surface area) and impurities in the surface of the ice reflect almost all light, but it is diffuse reflection (not like the surface of water) so it just looks white.

Answer 2

The ocean is blue (and sometimes a light green) not because it reflects the sky, but because it scatters light the same way the sky does. When light enters the ocean, the blue in it is scattered all over, so you can actually see it. The other colors just flow by.

The ice, however, reflects all visible wavelenghts in a similar fashion, so it would look white to us (white is the combination of all colors). But, if you were standing inside a glacier, the light that passed through the ice would also have had it's blue scattered - it's a property of water.

See this pretty picture:

http://www.usnews.com/usnews/photography...

That guy is inside a glacier.

Answer 3

the ocean isn't blue it is transparent but it reflects the colour of the sky and the glaciers are white because they are ice and ice it is white

Answer 4

The ocean is blue mostly because the sky is blue because blue light gets scattered more in the atmosphere.  Water also has a slightly bluish tinge even apart from that because it has vibrational resonances in the near infrared (that absorb into the visible red a bit).

Ice has those same resonances, so very pure ice that is frozen just perfectly is pretty clear and has a slightly blue tint.  Actual ice seems to be filled and covered with imperfections that scatter light every which way.  So it's pretty much just a diffuse reflector--ie looks white.

Marcos--What your saying about scattering in the water makes some sense, but I'm not sure I believe 100% that it's the explanation.  If scattering were the dominant effect, then when you shine white light straight through water, it should look reddish straight-on and blueish from the sides.  I think it look blue-ish even straight on.  Maybe you have both effects going on, so it looks even bluer from the sides.  And maybe the amount of junk in the water affects it.  In optics I remember running light through water with chalk in it, and the results from the scattering were consistent with what you describe.  Hmmm.  Let's see what we can dig up.

For what it's worth, this NASA sight for kids cites my secondary reason (water's vibrational resonances make it absorb red light more) as the primary reason the ocean looks blue from space.  They don't mention the atmosphere.  I think I'm inclined to believe what they say.

http://kids.earth.nasa.gov/seawifs/ocean...

This website cites all the reasons as contributing factors and agrees with the NASA cite that water's inherent blueness is primary.  And it gives a name to the "blue light from sky making water look blue" phenomenon--Montana reflection

http://www.webexhibits.org/causesofcolor...

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So after research, the #1 answer seems to be:

The ocean is blue because water is inherently bluish because of it's vibrational resonances in the IR and visible red energy levels.

Answer 5

i dont know but good question!

Answer 6

Ice is white because it reflects white light waves and absorbs all the other colored light waves.

Answer 7

glaciers are ice that has all the

minerals pressed out