Rookie Science: Luminescence

Kids Club
Video Transcript:

Hi there, I’m Larisa, I am children’s staff member at Charlotte Mecklenburg Library, and I’m here to do some Rookie Science with you today. Today we are going to be exploring luminescence which is light that creates light without making heat. If you touch a lightbulb, that’s incandescent, and that’s hot. But things like glow sticks glow without making heat. And the way you make a glow stick glow is crack it open. Uh-oh. Some of them are harder than others. And the way that that works is there is a little glass vial inside a glow stick that has one chemical, and then around the outside of that glass vial is another chemical. When they mix, they have a reaction and the result of the reaction is the glowing. Now an interesting thing happens with reactions—they are effected by the temperature that surrounds them. So we’ve got three cups of water. But let’s test out and see what we observe about the cups of water. This first one has ice floating in it. If you put your finger in it—brrr—that’s cold. The middle one doesn’t have ice, and if you put your finger in it, it just feels like the room temperature. It’s regular water. And then the third one; you’ll notice it has a little bit of condensation on the inside. If you put your finger in it—ouch—that’s hot. So what we’re going to do today, is we’re going to test what happens to the reaction going on inside the glow stick when we stick it in all three of these cups. So, let’s start with the middle cup first. It’s a little cool, and look the glowing is slowing down just a little bit. Hmm. That’s room temperature water. Let’s try it in the ice water and see what happens. We’ve got it floating in with the ice cubes. And going to give it just a little moment. See what happens. And pull it out—the glowing has gotten a little lighter—it’s not glowing as strongly as it was. That is because the cold has slowed the reaction down. So it’s not glowing as strong as it was because the reaction isn’t happening as fast. Well, if cold makes the reaction slow down, let’s find out what happens when we put it into hot water. Let’s see—we’re going to let it just sit there and take a little bath for a moment. Just observe it—we’re going to watch and see what happens. And I see it getting dark already. The hot is speeding up the reaction. So it’s starting to glow a little more strongly. If we let it just sit there, it’s going to keep getting stronger. I am going to take it out so you can see. And then put it back in. We’re going to let it glow a little bit longer. So, the cold water slows the reaction down. The hot water speeds the reaction up. That’s why if you’ve ever had a glow stick and you wanted to save it, someone might have told you to put it in the freezer because that slows the reaction down, so you can extend its life a little bit. And that is an exploration of luminescence with glow sticks.

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