How To Create A Prism

A prism is any object that separates white light into the colors of the rainbow — red, orange, yellow, green, blue, indigo, and violet. It works by refracting light, and breaking it according to its wavelength. You can purchase a triangular prism of glass or plastic from hobby stores, and you can also make a prism from a simple glass of water.

Step 1

Fill the glass with water so that it's slightly more than half full. Place the glass on the edge of a coffee table or other flat surface, so that almost half of the glass's bottom hangs over the edge. Be careful that the glass does not fall over the edge.

Step 2

Place the two sheets of paper side by side on the floor next to the coffee table. Turn the flashlight on and point it toward the glass so that the light goes through the glass and onto the sheets of paper on the floor.

Step 3

Adjust the position of the flashlight and the paper until you can see the characteristic rainbow on the sheets of paper. This may require a trial and error to get the angles just right. You may also get more than one rainbow.