Why is the sky blue can't the sky be pink of purple and why is the grass green? why?

Question

why is the sky this color?

why is the grass this color?

Answer 1

'Cause God decided it would be best that way.

Answer 2

The sky is blue because of the water droplets in the air that have condensed.

Grass in green because Green is the best color suited for solar absorption. The same goes with tree leaves.

Answer 3

First; why the sky is blue.

The answer "The sky is not blue" is not necessarily wrong.  The sky APPEARS to be blue; for the following reason:

I think most people know that sunlight is made up of light of several different wavelengths, and can be split up into the colours of the rainbow. Blue light has the shorter wavelength, and red the longest wavelength.

When sunlight hits the molecules in the atmosphere, the light is absorbed; causing the molecules vibrate and and give off, or 're-emit' the light. This is called 'Rayleigh Scattering'. Because the molecules vibrate in all directions, the light is emitted in all directions (called 'scattering'). Because the blue wavelength is shorter and more energetic than the red or yellow, it reacts much more with the air molecules, which tend to pass straight through.

Because the blue radiation is re-emitted from the air molecules in all directions, it seems to us looking from the ground that the blue light is coming from everywhere; hence the sky seems blue.

Near sunset, because of the low angle of the sunlight, the blue light has already been scattered away, and we see more of the red and yellow wavelendth, hence the colours of the setting sun.

The grass is green however; because it is REALLY green.  Just like our blood is red because of the haemoglobin in the red blood cells, the grass is green because special cells called chloroplasts contain chlorophyll, which is the chemical that uses the energy of sunlight to turn carbon dioxide into sugar.  Chlorophyll has a natural green colour.