In Oliver Sacks' book Uncle Tungsten: Memories of a Chemical Boyhood, he describes walking around with a pocket spectroscope, observing the bright and dark lines in the spectra of different types of light sources.
Instead of buying the lovely model above from Educational Innovations, however, we followed Simon Quellen Field's directions for a home-made spectroscope on his website scitoys.com. (It's also in his book,Gonzo Gizmos: Projects & Devices to Channel Your Inner Geek.)
Here's Field's explanation of what's going on:
A spectroscope is a device that lets us find out what things are made of. It works by taking light and splitting it up into its component colors. Different elements make different colors when they glow. We can make objects and gasses glow by heating them up in a flame, or by passing electricity through them. The spectroscope spreads out the colors of the light, and we can identify the elements by the bright lines we see in the spectroscope.We pretty much followed Field's directions, except for using duct tape instead of aluminum tape.
The razor blade slit, which is where the light comes in, was also finished off with duct tape. I forgot to take a picture of the placement of the DVD; we measured the distance from the slit to the end of the box and marked a line for the left edge of the disc. (See Field's directions to figure out what I'm talking about.)
We used it on incandescent and fluorescent bulbs and sunlight, and it seems to work pretty well. I noticed that along with the spectrum, you get a pinhole camera effect. We'll have to find some other light sources to test it out on.