observe the colour ocean and the sky when both of them appear blue though they are apart from each other why give reason
Answers
When sunlight falls on water some part of it is reflected back and other enters the ocean. The light gets scattered after entering the ocean by ripples and other particles in it.
Oxygen present in the deep water bodies scatter blue light more as compared to less deep water bodies. This is one factor why ocean appears blue.
Other reason is that when sunlight falls on water the part of light is reflected back which reflects colour of the sky.
The clear daytime sky is blue because the shorter wavelengths of light (such as blue) are "scattered" most by the molecules of the atmosphere. So in all directions away from the Sun we usually see blue sky. That's called "Rayleigh scattering".
That's also the reason sunrises and sunsets often appear red. The longer wavelength red light is not scattered much and the sky near the Sun appears red. The red sky near the Sun at sunrise and sunset is because the light has to travel through more air when the Sun is near the horizon and so the scattering of blue light is greater than at other times.
Obviously the clear night sky is black (apart from the Moon, stars and so on) because the Sun is not in the sky.
However, there is something called "Olbers' paradox" which is about why starlight is not enough to light up the night sky, but that's a bit hard to explain. You can read about that if you wish, but it's complicated and involves cosmology (the Big Bang Theory). The explanation usually involves the age of the Universe, the speed of light, and the fact that the Universe is expanding, but there's still a bit of argument about what is the correct explanation.