Today I decided to do something a bit different for our STEM club. Instead of starting with a story, I decided to open the club with a science experiment. We were exploring the chemical reaction of light! It sounds complicated, yes, but if it is using glow sticks- that has girls STEM written all over it. Glow sticks are not complicated. Glow sticks are just plain fun!
I laid the glow sticks on the table and I got four “ooooooooohs” in unison. They couldn’t wait to get their hands on them. (Literally!)
After settling on their favorite color, we got down to the discussion part. What happens to a glow stick when you break it? Can you make it glow brighter? After some discussion they agree they thought it was possible to make it glow brighter…. but how? Baking soda, regular soda and a few other items I did not have in my classroom were suggested. Finally, one suggested water. We have water!!! But what type of water would make it work? Hot water? Cold water? or just room temperature water? The girls discussed and made their predictions. They all thought hot water would work.
We tested them and the results were clear almost immediately. The sticks placed in warm water were remarkably brighter. So how does this happen?
In general, the speed of a chemical reaction increases as the temperature increases. At a higher temperature, a larger fraction of the reacting molecules have sufficient energy to react upon collision; thus, at a higher temperature, the glow is brighter. The opposite happens at lower temperatures.
We talked about this a bit and then connected it to regular light bulbs. The hot water acts just like a battery would for a lightbulb. An outside source of energy excites atoms, causing them to release particles of light called photons. No… I did not use those exact words, but yes… they could see how the battery helped the lightbulb light up, just like heat caused the chemical reaction to interact more.
They were proud that their predictions were correct and they were then ready for the next task – building!
They each were given light-up legos called Laser Pegs to build with. They had to build a structure that would use the glow stick in some way.
They drove right in the task and the lights were exciting. This surprisingly caused them to bust into some impromptu christmas music. Since I was in no way, shape, or form in the mood to have “jingle bells” stuck in my head, I decided they should sing Halloween music. Not surprisingly, the 2nd grade overnight song began to fill the room.
Here is what the girls built:
The Eiffel Tower, a torch, and more! It was a fantastic afternoon.