Experiment with Glow Sticks
In this science experiment, kids use glow sticks to investigate chemical reactions.
Glow sticks glow because of a chemical reaction. This type of glow is called "chemoluminescence." To create this reaction, glow sticks have two different liquids inside: one contained in a glass vial, the other surrounding the glass vial and encased in the plastic stick. When you bend the plastic stick, you break open the glass vial, causing the two liquids to mix together; this creates the chemical reaction that produces light.
The light will continue to glow as long as the chemical reaction continues to occur. When you warm up a glow stick, you speed up the chemical reaction, causing the glow stick to glow more brightly (but last for a shorter period of time). When you cool down a glow stick, you slow down the chemical reaction, causing the light to dim (but last longer). This is why freezing your glow stick can make it last for more than one day!
This experiment involves hot water. Be sure not to heat the water to the point that it could burn someone.
- Clear cup or glass - 3 per student
- Ice water - enough to fill the glass
- Hot (but not boiling) water - enough to fill the glass
- room temperature water -- enough to fill the glass
- Glow stick (all the same color) - 4 per student
Pour the cold, room temperature and hot water into each of the three glasses.
"Snap" your glow sticks to activate the chemical reaction; try to listen for the sound of the tiny glass vial breaking inside. Observe how much light the sticks are giving off. Keep one stick out of the water as your "control" for the experiment (a control is like a baseline to compare things to), and place one stick into each of the three cups. What happens? You should see a significant difference in the straws in less than a minute.
The glow stick in the cold cup will glow more dimly while the straw in the hot water will glow more brightly. You can also switch the sticks back and forth to see what happens.
If there's time, check back on the sticks hourly until they stop glowing. Chart the amount of time each glowed. How did the reaction rate affect how long the stick glowed?
If you are doing this with a large group of kids and are low on supplies, consider having kids do this experiment in teams.