Materials: Neon bulb with resistor (from Radio Shack), two bulb sockets, incandescent bulb, fluorescent bulb, electrical cords with plugs, diffraction spectrographs, screws, wood.

Building Instructions: Place two bulb sockets and drilled piece of wood on a base of wood as shown and attach them. (Make sure the neon bulb is placed in the wood before gluing it in place – I used a hot-glue gun for this). Screw in bulbs and look at them in a darkened room with the spectroscopes and you should see the corresponding spectra.

Functions and use: You have probably seen spectrums produced by wedges of glass called prisms. Spectroscopes are devices that allow us to spread out light into its various color, like a prism and look at each of them closely. Many gases, when they glow in light bulbs, on stars, or in galaxies, produce special spectra which can be used to identify the gas that is glowing. When a gas glows it produces more energy at certain colors and these appear as bright lines in the spectrum. Each gas produces its own very unique spectrum. To use the spectroscopes in front of you, place the narrow end near your eye and the wide end near the bulb. Line up the thin slit in the wide end with the bulb and you should see a spectrum produced on both sides of the slit. The spectrum is produced using a special ‘grating’ which is basically a piece of plastic with thousands of small triangular grooves that act as tiny prisms.

In front of you are three different sources of light. On the left is a standard light bulb that uses heat to make a filament glow and produces a standard full spectrum with no bright lines. The middle bulb is a small neon bulb that has neon gas inside. It uses a high voltage to make the gas glow. If you get close enough to this bulb, you will see many bright lines in the yellow and red portions of the spectrum. Lastly, the bulb on the left is a fluorescent bulb that is filled with mercury gas. Notice that the bright lines from this bulb are very different from the neon bulb.