Kids love to play with glow sticks at nighttime festivals and parties. What makes them glow is the interaction between two chemicals: an oxalate, which includes special fluorescers, and an activator. One liquid floats in a very thin capsule in the plastic tube containing the other liquid. When the tube is bent, the thin capsule breaks and the two liquids mix together and glow.
It's also fun to make crafts using glow sticks and necklaces -- and they're perfect for Halloween. This scary spider can be hung from the branch of a tree, or indoors where someone is likely to bump into it. Once activated, the glow sticks last for about eight hours, so make the spider right before you need it.