Why does the sky appear blue and clouds white?

[AlchemistK]

The following are some very basic commonly observed phenomena of light.
I need the reasoning of the statements with as much detail as possible.


1. The sky appears blue.
2. Clouds appear white.(why don't they scatter light?)
3. The sky appears reddish during sunset or sunrise.
4. The sun appears oval during sunset or sunrise but circular at noon.

 

[G01]

https://www.physicsforums.com/showthread.php?t=94379

See #1 in above link.

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