Making Colored Lights

How could you make a light source such as a light bulb emit different colors of light using common household or laboratory materials? Would paint work?
- Norris Van Steven (age 18)
Cuba

Just putting thin paint right on the bulb doesn't sound like a great idea for the long term, although it should work for a while. The problem is that the paint will heat up and probably crack off or maybe even break the bulb. I have some amber tail-light car bulbs that are made with a thin amber coating, and they have exactly this problem- the coating flakes off. If thin colored plastic sheets are available, they can be placed a little farther from the bulb to reduce heating.

If you can get a few LEDs, they give off colored light directly. (The white ones are actually trickier to make than the colored ones.) They can be powered with simple batteries or with an ac-driven dc supply. They're much more efficient than incandescent bulbs to start with, and then become even more so if some of the incandescent light is thrown out as heat.

Mike W.

 

(published on 03/09/2014)