Crews on U.S. aircraft carriers are decked out in all manner of colorful garb, but it's for more than just fashion. Each color serves a purpose on board.

How many colors are in the rainbow? Seven said Sir Isaac Newton. Of course, Newton knew that a spectrum is just that, a continuous gradation from one color to another.

The Visible Spectrum. The colors of the rainbow, often remembered using the acronym ROYGBIV, correspond to specific wavelengths of light: 1. Red (approximately 620-750 nanometers) ...

Did you see a lot of rainbow colors on NFL sidelines? It's for a good cause. ... There's a good reason for the spectrum being shown. The NFL is partnering with the American Cancer Society.