I am afraid that by now there are more people who recognize this as the cover of a pink floyd album then there are those who know of this as a very real and iconic scientific experiment. Many people will have seen this image in some form, but if you glaze over it like any other picture, you are missing out. Give yourself a few minutes to really think about it.
"Dispersive prisms are used to break up light into its constituent spectral colors because the refractive index depends on frequency; the white light entering the prism is a mixture of different frequencies, each of which gets bent slightly differently. Blue light is slowed down more than red light and will therefore be bent more than red light." Wiki - Prism Optics