Fall is upon us and October is a month packed full of changing leaves and changing temperatures! To study the impact of temperature on chemical reactions, check out this fun experiment using glow sticks. These brightly colored sticks are synonymous with parties and goody bags and can be found in stores.
- Hot Water (no hotter than 120F)
- 2 clear Mason Jars
- 3 glow sticks
- Paper and pen/pencil
- Perform this experiment in a darkened room so you can see the glow sticks glowing. Start by bending one of the glow sticks until you hear it “snap.” The liquid will begin to glow. Make note of the temperature of the stick. Is it cold? Is it warm?
- Next, fill one of the jars with cold water – a mixture of water and ice.
- Have an adult fill the other jar with the hot water – no hotter than 120 degrees F – otherwise, it can melt the plastic of the glow stick.
- Bend 2 more glow sticks until they “snap.” Then place one stick in the container of cold water and one in the hot water.
- Set a timer for 5 minutes. Record your observations. Which glow stick is brighter?
- Switch the sticks between the hot water and cold water. How long does it take for the dim one to brighten? What happens to the brighter one?
Wow! What’s Happening?
This process is known as chemiluminescence – light being produced from a chemical reaction. The reaction between the chemicals in the light sticks produces energy within the stick. The atoms get excited causing a rise in the energy level of the electrons. When they return to their normal energy levels, they release that energy as light.
Temperature can speed up or slow down these reactions. In this case, the hotter water accelerates the reaction and the light stick glows brighter than the others.