"Why are there so many songs about rainbows?" sings Kermit the Frog in a song (about rainbows) called "Rainbow Connection" from 1979's "The Muppet Movie." And it's not just songs that feature rainbows ...

When light passes through certain objects—such as prisms, rain droplets, or a CD—the different wavelengths can be bent at different angles. This makes the colors separate, so we see them as the ...