Originally posted by dork3d:
Aiyah! Me just typed in as per the notes from NEA gave me mah...
Impurities is the source of why it gives rain clouds (cumulus clouds) grey colour look...
As at night as moonlight shines across the atmosphere into the clouds, distortion of lights through the impurity particles reflect out like a prism effect, thus making the cumulus clouds at night look reddish...
Hmm... sounds correct I think. Just reinforce a bit from my understanding.
Clouds that are grey contain a larger amount of water which will be able to block or absorb some of the sunlight. With a larger amount of water, there is probably also more particles in the water that also serve to block the sunlight. White clouds appear white because there is less water to block the sunlight.
As for the red cloud, it is like what is said in the wikipedia link posted in one of the post. It is due to light scattering and probably involves diffraction where light is bend (as in the prism effect u have mentioned). I would think that the moonlight, which we all know is light reflected on the moon from the sun, does attribute to the colour of the clouds.
