Naked Science Forum

General Science => General Science => Topic started by: Karen W. on 15/04/2007 23:35:21

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: Karen W. on 15/04/2007 23:35:21

I have a friend at school who wished me to ask this question. So why is snow white, or is it? We all want to know!

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: DrDick on 16/04/2007 00:25:33

First of all, normal light is composed of many different colors.

Essentially, the ice in a snow flake acts as a prism, breaking apart the light into all the colors of the rainbow.  There are many, many snowflakes, and many, many different locations on each snowflake breaking the light apart.  There are so many, in fact, that the different colors recombine to form white light by the time the light gets sent back to our eyes.  If you investigate a single snowflake at the right angle, you should be able to see the prism effect.

Dick

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: Karen W. on 16/04/2007 00:33:50

Thank you that is very cool! Dick.. next time I see some snow I will try to see that effect if I can..Hey does that then mean that white is a mix of all the colors? Eh? If so is it an equal amount of each color or do any of the colors dominate to make up the white color if it is?

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: DrDick on 16/04/2007 01:06:15

Yes, white is a mix of colors, but not necessarily a mix of all colors.  The white you see on your computer screen (or tv screen) is a mix of three colors (red, green, blue).

This is where the term "white noise" came from, too, being a broad mix of sound waves of different frequencies.

Dick

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: neilep on 16/04/2007 01:36:32

Here is a related thread...about polar bear hair whiteness......which is nice http://www.thenakedscientists.com/forum/index.php?topic=5929.msg58839;topicseen#msg58839

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: Karen W. on 16/04/2007 01:49:24

Yes I like that one I remember LOL I have read it before Kind Sir ..LOL you have a great memory!! I bet that is where I remember hearing some of that from.. LOL

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: paul.fr on 16/04/2007 09:31:17

since snow is frozen water, and we all know that frozen water is clear, why does snow have a distinctive color? To understand this, we need to back up and look at an individual piece of ice. Ice is not transparent; it's actually translucent. This means that the light photons don't pass right through the material in a direct path -- the material's particles change the light's direction. This happens because the distances between some atoms in the ice's molecular structure are close to the height of light wavelengths, which means the light photons will interact with the structures. The result is that the light photon's path is altered and it exits the ice in a different direction than it entered the ice.

Snow is a whole bunch of individual ice crystals arranged together. When a light photon enters a layer of snow, it goes through an ice crystal on the top, which changes its direction slightly and sends it on to a new ice crystal, which does the same thing. Basically, all the crystals bounce the light all around so that it comes right back out of the snow pile. It does the same thing to all the different light frequencies, so all colors of light are bounced back out. The "color" of all the frequencies in the visible spectrum combined in equal measure is white, so this is the color we see in snow, while it is not the color we see in the individual ice crystals that form snow.

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: Karen W. on 16/04/2007 09:52:28

So it is equal amounts of the colores that form the white we see in the snow as white.. Thanks paul that is a good explanation..

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: paul.fr on 16/04/2007 09:56:55

Quote from: Karen W. on 16/04/2007 09:52:28

So it is equal amounts of the colores that form the white we see in the snow as white.. Thanks paul that is a good explanation..

yes, George is realy you man when it comes to light and colours though.

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: Karen W. on 16/04/2007 10:00:11

Well you did just fine my friend Thank you!

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: that mad man on 16/04/2007 17:51:58

In the word of the late Frank Zappa:

"don't eat the yellow snow!"  [;D]

Bee

Title: WHY IS SNOW WHITE? ( NOT "SNOW WHITE AND THE SEVEN DWARFS")
Post by: Karen W. on 22/04/2007 07:44:44

To be sure!! LOL