Why does the sky looks blue and sea looks blue ?

This is a common belief, but it is simply not true.

The sky looks blue because the atmosphere contains a special mixture of gases that absorbs all colors of light except for blue - which it reflects back to our eyes. If there is no light, the sky isn't blue (You'll notice the sky is black at night).

Water looks blue for the simple fact that it is, in fact, blue. When you look at a glass of water, it appears clear because you're not looking at ENOUGH water. If you fill up a white bathtub with water and look down into it, you'll see a faint blue tint. That is because the layer of water you're looking at is very thick, and the blue tint is layered and concentrated. The sea is a few miles deep, so the blue tint is incredibly concentrated. Yes, the sky is reflected, but that's a VERY weak variable in the sea's overall color.

Fun fact: The same is true for glass, which actually has a subtle green tint.

Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

There is no single cause for the colors of the sea. What is seen depends in part on when and from where the sea is observed. Eminent authority can be found to support almost any explanation. Some explanations include absorption and scattering of light by pure water; suspended matter in sea water; the atmosphere; and color and brightness variations of the sky. For example, one theory is that when sunlight hits seawater, part of the white light, composed of different wavelengths of various colors, is absorbed, and some of the wavelengths are scattered after colliding with the water molecules. In clear water, red and infrared light are greatly absorbed but blue is least absorbed, so that the blue wavelengths are reflected out of the water. The blue effect requires a minimum depth of 10 feet (three meters) of water.

Transmitted light (from the sun, light bulbs, fire, etc) is made up of a spectrum of colors. The longest wavelengths of light are on the red end of the spectrum and the shortest wavelengths are on the blue/violet end of the spectrum.

When transmitted light such as sunlight enters our atmosphere it collides with the oxygen and nitrogen atoms. The color with the shorter wavelength is scattered more by this collision. Because violet and blue are the shortest wavelengths the sky appears to be violet / blue. But because our eyes are more sensitive to blue light than they are violet light, we perceive the sky as blue.

Our eyes contain thousand of rods and cones, which are the receptors for light. Whenever one of the 3 Stooges pokes you in the eye you see a giant blue spot. This is because the blue receptors have been activated. Blue is one of the primary colors and thus more easily activated and seen by our eyes.

Blue is also how I feel when my baby leaves and my hound dog dies. Also, how I feel when the cops pull me over and I see their blue lights flashing in my rear view mirror. Then, again, blue is the color of the K-mart special, so this color isn't all bad.

Why is the sky blue: Summary

So, why is the sky blue? It is because blue light from the sun strikes the air molecules and scatters and our eyes perceive it as blue.

Why is the sky blue: Short Summary

Why is the sky blue, you ask? Blue in sunlight collides with air molecules and our eyes see it as blue.

Why is the Sea Blue, for the same reason your Swimming Pool is, it reflects the Sky !!

Namaste

i am not sure about the answer.in my opinion,sky looks blue because the stratosphere is blue,the stratosphere is made up of O3 molecules,maybe the stratosphere can absorb all the color of a light except blue,so the blue color is reflected or refracted and it looks blue then.

sea looks blue because sky is blue.

This was elucidated by Sir C.V.Raman, Indian Physics Nobel Laureate.

Here is the explanation in his own words:

http://www.vidyaonline.net/arvindgupta/raman.htm

I am guessing because of the hydrogen in the air...also in the water but I am not a genius so this is just a guess.