A crystal object, such as cut glass, with at least three similar sides. Most images in this article are linked to more information. We see light that bounces off of things around us. When the light enters our eyes, special cells tell our brains about the light. These cells are called photoreceptors.
Light is made of little bits called photons.
When the sun shines, trillions and trillions of these little bits of light fall on the earth. The photons bounce off of almost everything and some of them enter our eyes. Those bits that enter our eyes allow us to see. Starting in the 1600s with Sir Isaac Newton , scientists have believed that there are different kinds of photons. Different types give rise to our sense of colors.