how come snow is white and ice is clear?

Answer 1

Light is made up of all the colours of the visible spectrum (red, orange, yellow, green, blue, ingigo, violet). When all these colours are present we have white light - this is what makes something appear white. If some colours were missing then we see things as different colours.

Ice is translucent and the light entering a piece of ice passes through it but as it does it changes direction. This explains why ice isn't completely clear - if the light passed straight through it then ice would have an appearance more like that of glass.

Snow is simply millions of tiny ice crystals next to each other. When light hits snow it travels through the uppermost ice crystals and the direction of the light is changed slightly. This light passes into the neighbouring ice crystal and again the direction of the light is changed. This happens over and over and some of the light is refrected so that it comes right back out of the snow. Because this light consists of equal amounts of all the colours of the spectrum we see it as white light - hence snow appears to be white when really it has no colour to it.

Answer 2

Snow forms differently than ice, but ice in nature is not actually clear. Have you ever seen an iceberg? Or a glacier? They appear blueish, but are usually opaque white. The depth of the ice, the purity, etc. all have to do with what color the ice will appear.

If you remember why things have color at all, it's because of reflection and absorption. Ice that is mostly clear is clear because it does not reflect light within the ice back to your eye. Snow reflects all light so it appears white. Black is caused by something absorbing the incoming visible radiation. Nothing is pure white or pure black (except a black hole). To be more accurate, nothing really has any color except that our eyes are able to see and our brains able to process the spectrum from 300-700 nm wavelength into what we know as color.

Some things "contain" colors because they actually radiate or re-radiate visible light (such as when you heat your stove and it turns red). But that is getting way off topic to your question.

Answer 3

Actually snow *is* clear. It's ice. If you look at larger and larger amounts of ice, or ice that's crushed into smaller and smaller bits, it will appear whiter. Ever see a snowflake under a microscope? Just like glass.
The white appearance is most likely because light is being refracted so so much due to the high number of micro-facets it interacts with. An ice cube will have relatively few faults and be fairly transparent, allowing one to see colors that are behind. Highly fractured or detailed ice, like snowflakes or crushed ice, will be more opaque.

Jim, dirty water obviously makes dirty ice. The questioner didn't ask about muddy water. The 4 answers before yours each described correctly the reason for snow looking white. Are you the one who thumbs-downed all 4 of these fine answers? And how can you be a scientist when you start off telling people never to make assumptions about the forces of nature? They are the only thing we CAN make assumptions about. Anyway, how does that relate to this question or your answer?

Answer 4

Snow appears white because there's MILLIONS of different crystals,. (thus facets), which are ALL reflecting light in LOTS of different directions,... It reflects SO much light, (being clear and shiny in millions of small places), that it acts like a massive reflector,.. thus looking white,.. HOWEVER Ice is usually clear because there's not anywhere near as much reflection going on,. it may only reflect on a few hundred individual surfaces, thus reflecting MUCH less light, plus it even formed in a totally different way,.. solid water, (by mass not hardness), froze gently and became ice,. but snow is fine droplets of water freezing as it was a vapour forming highly reflective, multi-angular crystals,.. there's your answer :)

Answer 5

First off, never make assumptions about the forces of nature. Not all snow is white and not all ice is clear.

Ice is frozen water. If the water is turbid, the ice will contain that silt and therefore the silt coloration.

http://www.newton.dep.anl.gov/askasci/phy99/phy99180.htm

Answer 6

Air.

If you shave ice, it no longer is clear. That's because the light disperses as it passes through ice/air surfaces.

In order to get clear ice, it has to be very still as it freezes. If it is roiled up, it entrains air, and it freezes cloudy.