(classical music)
(jazz music)
- Hey, it's me, Lauren.
You've seen glow sticks before.
They bring a festive glow to
Halloween trick-or-treating
and New Years Eve celebrations.
And they're useful gear for explorers
from scuba divers to spelunkers.
(techno music)
When you find a bunch of
people gathered to party
in the dark, at least a
few of them will probably
be wielding glow sticks.
(jazz music)
But what the heck are these things?
How do they work?
Glow sticks are powered
by a process called
chemiluminescence.
Don't let the name scare you.
Luminescence is just a fancy word for
any emission of light
not caused by heating.
The chemiluminescence 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 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 is a small glass vial in the tube.
This vial typically contains
a hydrogen peroxide solution
called the activator.
It's floating in a solution
containing a compound
called phenyl oxalate ester
and a fluorescent dye.
When you snap a glow
stick, the vial breaks,
and the hydrogen peroxide reacts
with the phenyl oxalate ester,
creating two other compounds,
phenol, and peroxy acid ester.
Still with me?
Good.
The peroxy acid stuff is
unstable, so it decomposes
and produces additional phenol.
It also produces a cyclic peroxy compound,
which decomposes to carbon dioxide.
This decomposition
releases energy to the dye.
The electrons in the dye's
atoms jump to a higher level,
then fall back down, releasing
energy in the form of light.
The other chemicals in the
fluorescent dye determine
the color of this light.
Now, all of 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 a few hours.
Warmer temperatures will
accelerate this reaction,
making the stick glow brighter,
but for a shorter period of time.
When it's cooler, the
reaction will slow down,
making the light dimmer.
Which means that if you want
to preserve your glow stick,
put 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 is that you do in the dark.
Thanks for watching.
Is there any other party science
that's always mystified you?
Let me know in the comments,
and be sure to subscribe
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a moment of brain stuff.
