BrainStuff Classics: How Do Glow Stick Work?

Glow sticks use a chemical reaction to create that soft, colorful glow. Learn how it works -- and how to make your glow sticks last longer -- in this classic episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeart Radio. Hey
brain Stuff. Lauren voc Obam here with another classic episode
from our former host, Christian Sagar. With Halloween coming up
and families preparing to engage in the safest possible trigger treating,
I was thinking about a more traditional piece of trigger
treat safety gear, the glow stick, and this one, Christian

(00:23):
breaks down how they work. Hey brain stuff, this is
Christian Sager. You have seen glow sticks before. I bet
they bring a festive glow to Halloween, trick or treating
and New Year's Eve celebrations. And they are a useful
gear for explorers, from scuba divers to spelunkers. When you
find a bunch of people gathered at a party in

(00:44):
the dark, at least a few of them will probably
be wielding glow sticks. But what the heck are these
things and how do they work? Well? Glow sticks are
powered by a process called kemma luminescence. Don't let the
name scare you. Luminescence is just a fancy word for
any emission of light not caused by heating. We see
luminescence and stuff like TVs, neon signs and fireflies. The

(01:08):
chemo Luminescence in glow sticks is a pretty simple reaction
caused by mixing chemical compounds. Compounds are made up of
different elements bonded together in specific proportions so that they
can't be mechanically separated. It takes a chemical reaction to
sort out, for example, the oxygen from the hydrogen in water.
When you mix a compound with other stuff, you can

(01:30):
set off that reaction, and as the atoms rearrange themselves,
they'll either absorb or release energy. If you look inside
a glow stick, you'll see that there's a small glass
vial in the tube. This file typically contains a hydrogen
peroxide solution called the activator. It's floating in a solution
containing a compound called phenol oxalate ester and a fluorescent dye.

(01:55):
You still with me, Okay. When you snap a glow stick,
the vile brakes and the hydrogen peroxide reacts with the
phenyl oxalate ester, creating two other compounds, phenol and a
paraoxy acid esther Okay, still with me again? Okay. This
para oxy acid stuff is unstable, so it decomposes and

(02:18):
produces additional phenol. It also produces a cyclic perioxy compound,
which decomposes to carbon dioxide. This decomposition releases energy to
the dye. The electrons in the dyes atoms jump to
a higher level than fall back down, releasing energy in
the form of light. The other chemicals in the fluorescent

(02:38):
dye determine the color of this light. All this happens
within moments of snapping and shaking your glow stick. Depending
on which compounds are used, the chemical reaction can continue
for anywhere from just a few minutes to hours. Warmer
temperatures will accelerate the reaction, making the stick glow brighter,
but for a shorter amount of time. When it's cooler,

(03:00):
the reaction will slow down, making the light dimmer, which
means that if you want to preserve your light stick,
put it in the freezer overnight. It won't stop the process,
but it will slow it down and drag out the reaction.
So it turns out that there's some pretty nifty science
behind the humble glow stick. Check it out the next
time you're scuba diving, partying, or you know, whatever it

(03:23):
is you do in the dark. Today's episode was written
by Ben Bolin and produced by Tyler clang. For more
on this and lots of other glowing topics, visit how
stuff works dot com. Brain Stuff is production of iHeart
Radio or more podcasts my heart Radio, visit the iHeart
Radio app, Apple Podcasts, or wherever you listen to your

(03:43):
favorite shows.