Why are Clouds white?

ZealScience

Quote by DaleSpam

My answer doesn't contradict rainbows. Those are generally caused by larger droplets of water where there is nice clean refraction and internal reflection rather than scattering. They are different processes that depend on different sizes of the droplets. This is why you see rainbows more around your sprinkler than around your teapot.

But rainbow is similar to prism also. How can rainbow be created if droplet diffract different frequencies exactly the same? Like what I said total internal reflection, refraction only create primary and secondary rainbows. But the difference in color is dispersed by droplets.

*DaveC426913*

Zeal: clouds are formed of droplets in the microns size, very close to the wavelength of light where Mie scattering occurs. Rainbows are formed of droplets many times larger than the wavelength of light, where normal refraction occurs.

You see clouds all the time but you only tend to see rainbows when there's actual rain.

I learned about Mie scattering with a 30 second visit to Wiki.

DaleSpam

Quote by ZealScience

How can rainbow be created if droplet diffract different frequencies exactly the same?

Diffraction is not relevant AFAIK. The small water droplets scatter all frequencies approximately the same. The larger droplets refract different wavelengths differently. You are mixing up different phenomena. Refraction is different from scattering is different from diffraction.

ZealScience

Quote by DaleSpam

Diffraction is not relevant AFAIK. The small water droplets scatter all frequencies approximately the same. The larger droplets refract different wavelengths differently. You are mixing up different phenomena. Refraction is different from scattering is different from diffraction.

Sorry, I mean refract, misprinted. But why doesn't scattering like that won't cause polarization of light? Because light scattered by air molecules is polarized.

DaleSpam

I don't know anything about the polarization of scattered light. Sorry. Perhaps the link on Mie scattering has something.

ZealScience

Quote by DaleSpam

I don't know anything about the polarization of scattered light. Sorry. Perhaps the link on Mie scattering has something.

Sorry, I don't know either, I just can't quite understand it, so I'm asking it. Because air molecules polarizes light by reflection. But the reflection of light is similar pattern to the mie scattering that I looked at. Sorry for my deficiency of knowledge in this area. But I just don't quite get it. Probably I can start a thread about that.

Redbelly98

The number of scattering events is important too. For just one scattering event (rainbows, blue sky), polarization and color-separating effects are easily visible.

For many many scattering events (clouds, whitewater), the polarization gets randomized, and colors get mixed together.

Similar Threads for: Why are Clouds white?
Thread	Forum	Replies
Red clouds	General Physics	13
plucking a white hair would result in more white hairs	Biology	2
Probability question - Bayes' Theorem - 4 Balls, 2 white, P(all white) = ?	Precalculus Mathematics Homework	4
White clouds and blue DVD?	General Physics	4
Clouds and CO2	Earth	7

DaveC426913	Zeal: clouds are formed of droplets in the microns size, very close to the wavelength of light where Mie scattering occurs. Rainbows are formed of droplets many times larger than the wavelength of light, where normal refraction occurs. You see clouds all the time but you only tend to see rainbows when there's actual rain. I learned about Mie scattering with a 30 second visit to Wiki.

DaleSpam Mentor	I don't know anything about the polarization of scattered light. Sorry. Perhaps the link on Mie scattering has something.

Redbelly98 Mentor Blog Entries: 10	The number of scattering events is important too. For just one scattering event (rainbows, blue sky), polarization and color-separating effects are easily visible. For many many scattering events (clouds, whitewater), the polarization gets randomized, and colors get mixed together.