White light is made out of many colors of light.
We can split these colors with a prism and see the spectrum.
How does a prism separate the different colors of light?
Basically as light passes from the air to the glass, it refracts (see more on refraction from this post). The different colors of light have different wavelengths. This causes them to refract at slightly different angles.
We used a flashlight and a prism to shine a spectrum on the snow at night (I figured that the nice white snow would not distort the colors). At first I was shining the spectrum far out into the yard. Then I tried to shine it closer. When I did, it just looked white, with a little color at the edges. Based on the previous paragraph, can you figure out why that happened?
If you don’t have a prism, here is a link where you can buy one: Prism. If you want to make a spectrum without buying a prism, I will be posting another method soon that just used common household supplies.
Check out the rest of the properties of light series here.