Rainbows

[angelmerlin]

I understand that a rainbow appears when sunlight is refracted through raindrops.  What happens when it snows?  No rainbow?

[NetSquirrel]

There is an excellent article that explains the way rainbows work here: http://science.howstuffworks.com/rainbow.htm.)

It is because raindrops are round and all virtually the same size that enables them to refract light in such a way as to create a rainbow.  (The diagrams on page 3 of the HowStuffWorks article illustrate this nicely.)  Snowflakes, on the other hand, are all different shapes and sizes and therefore refract and reflect the light falling on them in completely different ways, scattering the light in all directions.  In addition to this, they topple and spin on their way to the ground, so a group of falling snowflakes will never "line up" with each other and so cannot create any kind of refraction pattern at all.  They just appear white because of this.  (See question "why is snow white", 3 questions down from here.)

[THECORBYLOON]

I don't know if it mentions this on the website quoted by NetSqirrel but the rainbow you see is not the same one that anyone else sees.

[KebabMeister]

THECORBYLOON, you from Corby?

[THECORBYLOON]

KebabMeister, yes I am-why do you ask?

[KebabMeister]

Ah, I used to live in Oakham, the other side of Uppingham.  Used to go to Corby a fair bit to go shopping! :)  I live in M�nich, Germany now though but I still visit back home.

[RyanT]

Maybe because when it snows.... There is no bloody sun!

[angelmerlin]

On Friday I saw the sun shining through a snow shower in just the same way it does through rain. This prompted my question...

[Calvesy]

You do get rainbows formed by ice crystals around the sun and moon 22 degrees away from the source of light. Called a halo.

[incitatus]

you can also get rainbows formed by floating ice crystals on mountains.  Ive seen one, circular, much like the ones you see from planes.

[Peter Pedant]

a bit late I should have said these are 'sun dogs'