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Speaker 1: Deep in the back of your mind. You've always had

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Speaker 1: the feeling that there's something strange about reality. There is

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Speaker 1: super annoyed death, much nanopartic, mechanical messiahs, punch evolution. On

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Speaker 1: our award winning science podcast Stuff About Your Mind, we

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Speaker 1: examine neurological quandaries, cosmic mysteries, evolutionary marvels, and our trans

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Speaker 1: human future. New episodes come out Tuesdays and Thursdays on iTunes,

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Speaker 1: Google Play, Spotify and anywhere you get your podcast. Welcome

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Speaker 1: to brain Stuff from How Stuff Works. Hey, brain Stuff,

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Speaker 1: this is Christian Seger. You have seen glow sticks before.

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Speaker 1: I bet they bring a festive glow to Halloween, trick

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Speaker 1: or treating and New Year's Eve celebrations. And they are

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Speaker 1: a useful gear for explorers, from scuba divers to spelunkers.

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Speaker 1: When you find a bunch of people gathered at a

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Speaker 1: party in the dark, at least a few of them

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Speaker 1: will probably be wielding glow sticks. But what the heck

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Speaker 1: are these things and how do they work well? Glow

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Speaker 1: sticks are powered by a process called kemma luminescence. Don't

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Speaker 1: let the name scare you. Luminescence is just a fancy

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Speaker 1: word for any emission of light not caused by heating.

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Speaker 1: We see luminescence and stuff like TVs, neon signs and fireflies.

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Speaker 1: The chemo luminescence in glow sticks is a pretty simple

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Speaker 1: reaction caused by mixing chemical compounds. Compounds are made up

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Speaker 1: of different elements bonded together in specific proportions so that

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Speaker 1: they can't be mechanically separated. It takes a chemical reaction

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Speaker 1: to sort out, for example, the oxygen from the hydrogen

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Speaker 1: in water. When you mix a compound with other stuff,

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Speaker 1: you can set off that reaction, and as the atoms

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Speaker 1: rearrange themselves, they'll either absorb or release energy. If you

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Speaker 1: look inside a glow stick, you'll see that there's a

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Speaker 1: small glass vial in the tube. This file typically contains

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Speaker 1: a hydrogen peroxide solution called the activator. It's floating in

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Speaker 1: a solution containing a compound called phenol oxalate ester and

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Speaker 1: a fluorescent dye. You still with me, Okay. When you

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Speaker 1: snap a glow stick, the vile breaks and the hydrogen

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Speaker 1: peroxide reacts with the phenyl oxalate ester, creating two other compounds,

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Speaker 1: phenol and a paraoxy acid esther Okay, still with me again. Okay,

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Speaker 1: this paraoxy acid stuff is unstable, so it decomposes and

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Speaker 1: produces additional phenol. It also produces a cyclic perioxy compound,

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Speaker 1: which decomposes to carbon dioxide. This decomposition releases energy to

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Speaker 1: the dye. The electrons in the dyes atoms jump to

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Speaker 1: a higher level than fall back down, releasing energy in

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Speaker 1: the form of light. The other chemicals in the fluorescent

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Speaker 1: dye determine the color of this light. All this happens

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Speaker 1: within moments of snapping and shaking your glow stick. Depending

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Speaker 1: on which compounds are used, the chemical reaction can continue

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Speaker 1: for anywhere from just a few minutes to hours. Warmer

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Speaker 1: temperatures will accelerate the reaction, making the stick glow brighter,

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Speaker 1: but for a shorter amount of time. When it's cooler,

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Speaker 1: the reaction will slow down, making the light dimmer, Which

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Speaker 1: means that if you want to preserve your light stick,

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Speaker 1: put it in the freezer overnight. It won't stop the process,

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Speaker 1: but it will slow it down and drag out the reaction.

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Speaker 1: So it turns out that there's some pretty nifty science

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Speaker 1: behind the humble glow stick. Check it out the next

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Speaker 1: time you're scuba diving, partying, or you know whatever it

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Speaker 1: is you do in the dark. Check out the brain

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Speaker 1: stuff channel on YouTube, and for more on this and

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Speaker 1: thousands of other topics, visit how stuff works dot com.