How Do Glow Sticks Work?
Glow sticks are a nifty little invention, and one that most people take for granted. You snap them and then they light up- what’s the big deal? But, in fact, the chemistry behind how glow sticks work is fascinating. They contain a few key ingredients that, when mixed, undergo a chemical reaction that results in the characteristic bright, cheery glow.
What's in Glow Sticks?
Glow sticks of all shapes, sizes and colours contain two key ingredients: hydrogen peroxide and a phenyl oxalate ester. The hydrogen peroxide (H2O2) is encased in a thin glass tube within the glow stick, and the phenyl oxalate ester sits around it. It’s these two compounds that cause the glow of traditional glow sticks. To get the wide range of colours that make glow sticks so distinctive several different types of fluorescent dyes are used. For red, rhodamine B. For yellow, rubrene. For blue, diphenylanthracene. For green, it’s 9,10-bis(phenylethynyl)anthracene. A bit of a mouthful, I know. The technical names of the dyes aren’t particularly important; it’s their effect that matters, and I go into detail about this in the next paragraph.
Name of Compound
Location in Glow Stick
Inner glass tube
Mixes with the other solutions to initiate the reaction
Phenyl oxalate ester
Around the glass tube
Releases energy during decompositon
Around the glass tube
Provides electrons that move from higher to lower energy levels, giving off different coloured lights
How do Glow Sticks Work?
When you crack a glow stick and it makes that satisfying crunching noise what you’re really doing is breaking the thin glass tube inside and allowing the hydrogen peroxide solution to mix with the phenyl oxalate ester and the dye. As the three liquids mix together they undergo a chemical reaction. The hydrogen peroxide and the ester react first, producing a different compound called phenol and a peroxyacid ester. The peroxyacid ester is highly unstable and goes through several different stages of decomposition into other compounds. Each of these stages releases energy.
Phew. Still with me?
The energy created is funnelled into the dye compound. Electrons within the dye are excited by all of the extra energy flooding in, but eventually fall back down to their resting state. As they fall from an energetic state to a less energetic state they release coloured light. This overall reaction is called chemiluminescence, and it’s what makes glow sticks light up.
Are There Different Types of Glow Sticks?
Glow sticks come in all shapes and sizes. There’s your average 'party' glow sticks with their bright colours and short lived luminescence, there’s long lived, plainer glow sticks to provide light for camping and there’s even glow sticks designed to light up the depths of the ocean for deep sea divers. There are minor differences in the composition of these different types of glow sticks of course, but essentially they all work in the same basic way. Hydrogen peroxide and phenyl oxalate ester (in some cases tert-butyl alcohol can be used instead) combine and then you get glow.
Are Glow Sticks Dangerous?
Since glow sticks are completely sealed they normally don’t pose a very serious safety hazard. The concern over glow stick safety generally comes from parents who are worried about their children biting down on the smooth, chewy, inviting 'toys' and ingesting their contents. None of the chemicals in glow sticks are known for being particularly toxic. The general advice circulating on the internet is to flush out the mouth, eyes, or whatever body part makes contact with the chemicals thoroughly and then to call poison control. All in all glow sticks aren’t all that dangerous, although their contents still don’t taste very nice and chowing down on one isn’t recommended (I ate a glow stick once when I was six, so I’m actually an authority on this).
Did you ever bite into a glow stick as a kid?
Who Invented Glow Sticks?
The title for the inventor of the glow stick is a highly contested one. Most glow-enthusiasts, however, credit one Edwin A. Chandross, a chemist from Brooklyn, with the invention. Chandross discovered that a combination of hydrogen peroxide, oxalyl chloride and dye produced an interesting reaction that gave off light. His interest was more academic than commercial so he never filed a patent on the discovery (his loss, I guess). Instead, Michael Rauhut, a worker a chemical manufacturing company, jumped at the opportunity to carry Chandross’ work forward and found that using phenyl oxalate esters increased the glow-power of the reaction ten fold. The company he worked for eventually sold the rights to this discovery to another company, who sold it to another company, and as a result of this confusing mess there are more than five seperate patents for the technology.
Cool Glow Stick Hacks
- To lengthen the time your glow stick works for make sure to keep it in a cooler environment like a fridge or freezer. The cooler temperature slows down the reaction, so the glow stick will dim a bit but will last for much longer.
- To make your glow stick brighter try heating it up. The heat speeds up the reaction and increases the amount of light energy emitted, although this will shorten the duration of the glow considerably.
- Try attaching glow sticks to your ceiling fan. The effect is pretty awesome.
To recap, glow sticks contain a glass tube of hydrogen peroxide floating in a solution of a phenyl oxalate ester and a fluorescent dye. When you crack the glow stick the glass tube breaks and the chemicals mix together, undergoing a chemical reaction known as chemiluminescence. There are many types of glow sticks, but most of them work based on this same reaction. Glow sticks aren’t particularly dangerous, but you should avoid eating them, and the guy who discovered the original reaction and arguably invented the glow stick didn’t patent his invention and didn’t get any money from it. Idiot.
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© 2018 K S Lane