From 1665 to 1666, Isaac Newton studied sunlight and discovered that it can be broken down into a rainbow of colors with a prism. Today, we know that the rainbow of colors is a consequence of bending the different wavelengths of different colors. “White” sunlight is not really white—there is no wavelength of light that is white. Rather, it is a mixture of many different colors that appears white to our brains after being processed by our eyes and optic nerves.
Like transverse waves, light waves are characterized by amplitude, wavelength, and velocity. Unlike other waves, light waves—and all electromagnetic waves—can be transmitted through a vacuum, because they propagate as a result of oscillating electric and magnetic fields. They can reflect off surfaces and be refracted, and the change in angle as they travel from one medium to another can be calculated using Snell's Law. When the angle is large enough, the light rays can undergo total internal reflection.