What is light exactly, i mean, it's not something you can see while it's in air, and does light is what interact with some chimicals that are in everything, to generate colours? also, what are colours? are they chimical interact with light or what? for example if you was in a dark room, no light in it, and all closed, you'll see everything in black, no colours, all in black. does colours exist? or it's just our eyes, that gives us the ability to see some interacts wich are colours, for example, some animas only see in black and white, i think it's the dog, or the cat, some others, see in red, i mean, see everything "redish", like some snakes, or all snakes, anyway... so what is light exactly, and what are colours?