Inventor's Lab GET GLOWING

Sir Isaac Newton experimented with his own eye to learn about human sight, but you can learn about how light works without poking your eye.

First, remember that black lights give off light that is ultraviolet, and human eyes cannot naturally see ultraviolet light. But phosphors absorb radiation and reflect it back as visible light. Petroleum jelly contains phosphors, so it will absorb the ultraviolet radiation and reflect it back in a form of light the human eye can see.

Use these materials to experiment with what makes things glow in the dark.

MATERIALS

Dip your finger in the petroleum jelly and write a word on the paper. When you are done, turn off the room light and turn on the black light. Can you see the light from the phosphors? Next, cover one hand in petroleum jelly and look at it under the black light.

Is there anything else you can find that glows under the black light? Often laundry detergents contain phosphors and may make white clothes glow in black light.

How can you use this new knowledge? Can you write secret notes to your friends? Plan a scary black light Halloween party?