A prism, like the one in the Figure below , can be used to separate visible light into its different colors. A prism is a pyramid-shaped object made of transparent matter, usually clear glass or plastic. Matter that is transparent allows light to pass through it. A prism transmits light but slows it down. When light passes from air to the glass of the prism, the change in speed causes the light to change direction and bend. Different wavelengths of light bend at different angles. This makes the beam of light separate into light of different wavelengths. What we see is a rainbow of colors. For an animated version of the prism below, go to this URL: http://en.wikipedia.org/wiki/File:Light_dispersion_conceptual_waves.gif
Marks science teacher gave each student something that looked like a thick pyramid of glass he called a prism. He asked them to hold it up to the light and look through it. He wanted them to look at the light in the air and as it passed through the prism. When Mark did he saw several different colored beams of light.
Was the colored light all one wavelength or different?