Halloween Science with UV Light


This post originally ran in October, 2022.


Let’s try some Halloween science activities with UV light. Ultraviolet lights, or black lights, are prevalent this time of year in Halloween decorating, so why not use them to make our activities more interesting, too?


Halloween Science with UV Light

UV Light Safety

You should always read the safety precautions that come with your black lights. Those in the party or Halloween sections are most likely safe. Double-check the information that came with your black light, and be sure it is meant for entertainment use. Some black lights are created for medical or scientific purposes, so don’t just buy whatever light you happen to see online. Ultraviolet light can be dangerous depending on the type of light and exposure time. Some black lights require wearing special UV safety glasses or goggles and covering exposed skin or minimizing the length of exposure. UV light is the type of light that causes sunburns, after all.

You should also remind everyone not to look directly into the black light (just like you wouldn’t look directly into the sun).


 What Glows Under a Black Light?

It’s fun to take a small handheld black light and see what items in your house will glow under the black light. We found that the googly eyes glow under UV light.



Try tonic water, toothpaste, toys, paper, spices, food, money, rocks, minerals, and even urine. Because of the phosphorus content, urine glows yellowish-green under UV light. You may or may not want to check out the bathroom with the black light.


Make a Sensory Bin

Take something that glows under the black light and mix it with a filler that doesn’t glow. Here I’ve used glow-in-the-dark stars and dyed chickpeas. Dried rice, oatmeal, rocks, sand, and other sensory bin bases would work just as well.




Add a Black Light to a Science or Art Activity

Make a regular science or art activity extra special by using black lights.

Slime is one of my favorites. Here I’ve used Steve Spangler’s Atomic Slime that glows under UV light. 



I also love using neon oil pastels in art activities. Most of the colors of neon oil pastels glow brightly under a black light. You can also use neon crayons, but only some of the crayon colors will glow under the black light.



Combine the neon oil pastels with liquid watercolors and diffusing paper, and you’ll get my Glowing Halloween Art project.

Glow-in-the-dark paints or neon paints usually glow under a black light. Painting a pumpkin under a black light would be super fun.


What glowing black light ideas will you try?