Why is snow and ice white when water is see-through?

Question

I've been wondering this for a while...help me please?

Answer 1

this is the effect of crystalization. when water start to freez , the molecules start to arrange in some geometric shapes and form hexagonal crystals , this crystal form  prevent light from passing through the crystal lattice , all the fallen light is scatterd back . then it become non transparent and white.

Answer 2

The whiteness of snow is produced by tiny air bubbles which form almost 80% of the volume of snow on the ground.

Answer 3

This is a good question.

Certainly air bubbles in ice have an effect of making them appear white, but WHY this happens is interesting (and water particles don't have to have air bubbles in them to appear white; or even to be made of ice particles, like snow - your question could equally be "Why do clouds appear white, but water is see-through")

The answer is an effect called miele scattering.  When light passes through a mass of very fine particles, like the tiny droplets in clouds or a mass of snow flakes, the light is partly absorbed by the particles, and then re-emitted.  If the particles are relatively large, in comparison to the wavelength of visible light, then the light will be emitted at all visible wavelengths; and hence it appears white.  This happens with fine droplets of water, snow, or foam in a breaking wave; as well as with smoke.  

If there is a lot of the tiny particles; then less and less light will eventually pass through, and the material will appear dark. (That is why thin, fluffy clouds are white; but dense stormy ones are grey or black).

If on the other hand, the particles are much smaller than the wavelength of light; then when the light is re-emitted or 'scattered', it is re-emitted at the same wavelength as the light that strikes the particle.  The shorter the wavelength of the light, the more this effect happens.  This is called "Rayleigh scattering".  In the atmosphere, the tiny molecules in the air scatter the light in this way; and because the blue wavelength of light is shorter than the red or yellow; it is the blue wavelength that gets scattered.  We see this on the ground, as the blue colour of the sky.

So on a partly cloudy day; we see white clouds due to Miele scattering in a field of blue sky caussed by Rayleigh scattering.

Incidentally, up close there is less miele  scattering; so a single snow flake may appear clear.

Answer 4

Pure ice with a smooth surface is clear.  It's surface defects that cause light to be scattered in all directions, making it impossible to view an image through it.  Also, air dissolved in water forms bubbles as it freezes.

Water, of course, can't be scratched, so its surface is always smooth.