why are the clouds white?

Why is the sky blue? It’s a classic question – probably the classic question of the genre of explanatory popular physics. The famous short version of the answer is that Rayleigh scattering by air molecules affects short-waveength light more than long-wavelength light, and so blue light tends to get scattered in random directions to create the diffuse blue we know and love.

so, can we find the same answer for a similar question: why are the clouds white?
-Matt Springer

Take your own cloud picture and share what it tells you.