why is the sky blueWhy is the sky blue and why are clouds white?

I know it has something to do with molecules, but why blue?
And I have no Idea why the clouds are white.
-The-re is a physical phenomenon called Rayleigh scattering that causes light to scatter when it passes through particles that have a diameter one-tenth that of the wavelength (color) of the light. Sunlight is made up of all different colors of light, but because of the elements in the atmosphere the color blue is scattered much more efficiently than the other colors.
When you look at the sky on a clear day, you can see the sun as a bright disk. The blueness you see everywhere else is all of the atoms in the atmosphere scattering blue light toward you. Because red light, yellow light, green light and the other colors aren't scattered nearly as well, you see the sky- as blue.
As explained in "Why do we have blue skies", white light from the sun consists of all the colors of the rainbow. Since light travels as waves of different lengths, each color has its very own unique wavelength.
In much the same way as why skies are blue, clouds are white because their water droplets or ice crystals are large enough to scatter the light of the seven wavelengths (red, orange, yellow, green, blue, indigo, and violet), which combine to produce white light. Clouds will appear dark or gray when either they are in another clouds shadow or the top of a cloud casts a shadow upon its own base.
The darkness of a cloud also depends on the background sky. A cloud will look darker when it is surrounded by a bright sky and lighter when it is in front of darker ones. Not always will a dark cloud mean rain.
More often, the reason we experience dark rainy days is because clouds are blocking the sunlight. Some of the whitest, most pure light can be observed when dark clouds "break apart" and sunlight filters through.
Food coloring! Hellllooooo?!

Sky is not blue , Its black . Its due to dispersion from the sun that it appears to be blue, since blue color has highest wavelength so it gets dispersed the most . If u go to the outer space u will find that the whole universe is dark black.
Clouds are white because they are made up of water vapors.If the clouds are light and do not contain much water to cause rawhy is the sky bluein then they are white . You must have observed that they turn dark gray just before the rain starts !. Its because just before the rain , they contain a lot of water , so sun light is unable to penetrate through them due to which they appear dark ... !
The sky is blue because the molecules in the air scatter light in the higher wavelengths (that is, the blue light), while lower wavelength light (that is, the light on the red end of the spectrum) goes through to the ground. So the light that get finally reflected down from the scattering is blue, therefore a blue sky. This is called Rayleigh Scattering.

Clouds are usually white due to the reflection of light off the water vapor and the ice crystals in the clouds.

wl
The sky isn't blue, it's black, and the color we see has nothing to do with any reflection of the ocean. The atmosphere just gets in the way, in a manner that when we look up we see blue. This atmosphere is primarily nitrogen-oxygen. The Sun puts out everything from high-energy gamma-rays to low-energy radio waves. They take about 8 minutes for those photons (packets of light) to reach us.

When they do, the high-energy gamma-rays pass the exosphere, get into the thermosphere, but are stopped quite quickly by the ionosphere, which is at the base of the magnetosphere (the field created by our magnetic field, which deflects X-rays and cosmic rays that would kill us). The ionosphere is an area where atoms have had electrons ripped from them ("ionized"), which makes them good at absorbing gamma-rays (which would also kill us, like the other high-energy rays). Incidentally, it's also why we use it to bounce radio signals over long distances. So now the gamma-rays are gone.

The rest of the spectrum continues deeper into the atmosphere, until it gets to the stratosphere, and hits the ozone layer. The ozone layer is to ultraviolet (UV) light what the ionosphere is to gamma-rays. It absorbs them, blunts them, stops them (a neat process, below if you want to know more).

The rest of the spectrum continues on. The low-energy photons, beginning with radio, going to infrared, red, orange, yellow, and even green just blow right through to the surface, where the infrared provides heat (IR light = thermal energy), and the other light provides visible light. So green iwhy is the sky blues gone.

So what's left? Blue, violet, and indigo.

Our atmosphere loves blue. Particularly blue (475 nm). So now, when a blue photon strikes an atmospheric molecule, one of two things will happen:

(1) It will it the molecule and bounce off in a random direction. Think of it as setting a basketball down fifteen feet away, then taking a golf ball, throw it at the basketball, and try to guess which way it's going to bounce.

(2) It will be absorbed by the molecule, and instantaneously processed and spit out (re-emitted) in a completely random direction.

Awesome. But, this bounced or re-emitted photon can't go very far until it'll hit another molecule, at which point, again either (1) or (2) will happen. Then it happens again... again... again until you have billions of blue photons bouncing all over the sky, just covering it in the color blue. This is the Tyndall effect, though we all know it as Rayleigh scattering. Tyndall was a civilian scientist who discovered it first, Rayleigh was a British lord who discovered it second -- title goes to British lord. I know, it's not fair. In any case, it's because of this scattering that everyone on Earth can look up during the day, and we'll all see the exact same blue sky (our eyes might interpret the color differently, but that's a biology matter). At any rate, this is why everyone on Earth can look up during the day and see the same blue sky.

Now, I haven't forgotten about the indigo and violet photons (did you?). They're being scattered similar to the blue photons, but not as effectively because of their wavelength.

Consider that the human eye is not designed to see the indigos and violets very well, and our atmospheric molecules don't bounce and absorb indigoes and violets very well, and the overall effect is that we see the sky as blue (with violet and indigo tinting that we don't notice). As long as sunlight is hitting the atmosphere, we see blue. But when the Sun goes out at night - the blue goes away.

Clouds are white because they're composed of both water vapor and ice crystals, which when hit by sunlight will appear white, as they reflect all colors of the visible spectrum.