A simple object in your own house can break apart light into different colors. Every notice how a CD seems to create rainbows? The surface of the CD has many fine grooves, which acts as a spectrograph when light reflects off of it. In a darkened room, turn on a single light bulb. Look at the rainbow that it produces. Try this with other kinds of lights, including LEDs and outdoor lighting. For each kind of light, describe the type of light, and the spectrum. Check out Figure 1 as an example. Is it continuous, or just a few colors? Which colors? Do not use your CD to look at the spectrum of the sun — you could hurt yourself and a penalty will be applied to your grade. (A DVD works reasonably well for this, but a Blu-ray disk doesn’t work at all well.)
Figure 1. Spectra of a high pressure sodium light (the pinkish-white outdoor lights). Notice that the spectra is not continuous: most of the green and nearly all of the blue is missing. At higher resolution, you’d actually see a collection of distinct colors, mostly in the yellow to orange part of the spectrum.