There are many colors in nature. But do you know if a color has weight? I think you'll say "no". But I am afraid you are wrong. If you don't believe, you may do a small experiment. First, put two objects  with the same weight into two boxes. Then cover the box. Third, wrap  one box with a red piece of paper, the other with a white piece of paper. OK. Now hold the boxes with your hand one by one. It is certain that you will think the red one is a little heavier. Why do you think so? A scientist found that different colors have different weights in a man's mind. So he did many tests and at last he got the result. That is to say, every color has its own weight in our mind and their order is the same. The heaviest color is red, then blue, green, yellow and white. The scientist told us that colors also have smell. Can you smell the color? Of course not. Then why did the scientist say so? That is because every color stands for  a kind of light with a certain wavelength . It reaches our brain through sense organs . According to this discovery, scientists say that people accept the colors they like, and refuse the colors they hate. So your body and mind will be healthy by using the colors you like. Or you'll be nervous or ill. For example, if you stay in a room with red windows, wallpapers and furniture for two hours, you'll feel you have been there for four hours. But if the room is blue, you'll feel you have been there for only an hour. Another example, if a person walks out of a red room and into a blue room, his temperature will fall. That means our body temperature will change with different colors. Why did the scientist say colors have smell?
Because people can sense  the light from colors. Because we can smell colors with our noses. Because every color has its own sweet smell. Because every color can give off light of the same length.