Ultra-Violet Spectra
Your skin is also an excellent detector of ultraviolet (UV) radiation. When you expose bare skin to sunlight, your skin will either turn brown (a suntan) or red (a sunburn). These responses by your skin are a signal that the cells under your skin are being assaulted by UV radiation. UV radiation wavelengths are short enough to break chemical bonds in your skin tissue and over prolonged exposure, your skin may wrinkle or skin cancer may appear.

There is a safer way to detect UV--by using UV beads. These plastic beads contain a chemical which changes color when exposed to UV radiation. The colors that develop depend on the wavelength of the UV radiation.

Things To Do:

1. Place a selection of UV beads near a fluorescent light. Do any of the beads change color? Can you get a sunburn or a tan by sitting next to a fluorescent light?

2. Take the UV beads outside, but not into direct sunlight. Do any beads change color? Is there UV radiation in the shade?

3. Now place the beads in direct sunlight. What do you notice about the intensity of the beads' color?

4. Place the beads in direct sunlight and place a sheet of thin plastic over them and note the colors. Now spread on a layer of a commercial sun block on the plastic and note if any of the bead colors are reduced. Try this experiment with a number of sun blocks with different ratings. Which brand and which ratings block solar UV most effectively?

5. If you are able, take the beads to a tanning parlor and expose them to the UV radiation from the tanning lamps. How does this UV radiation compare to the sun's UV?

6. If you take a trip into the mountains, take the beads along and see if there is any difference between colors at high altitudes and at sea level.

You can purchase UV beads from:

Educational Innovations, Inc.
362 Main Avenue
Norwalk, CT  06851
Toll Free: 888-912-7474
Direct link to UV Bead page


Arbor Scientific
P.O. Box 2750
Ann Arbor, MI 48106-2750
Direct link to UV Bead page






Purpose & Discoveries

Purpose & Discoveries

Purpose & Discoveries

Purpose & Discoveries

Related Hands-on Activity

Related Hands-on Activity

Related Hands-on Activities
1. UV Beads
2. Spectroscope

Related Hands-on Activity

Created 1997 The Exploratorium 
Copyright Regents of the University of California