Tear Gas
Released on 04/04/2014
(playful music)
(snapping music)
[Narrator] In World War I,
toxic gas was a weapon of choice.
(gentle music)
Today, law enforcement uses a less potent recipe
to pacify a room or control a crowd.
But what's inside a can of tear gas?
It starts with charcoal.
That's wood burned until almost nothing is left but carbon,
just like in your backyard barbecue.
Charcoal keeps things smoking.
(bouncy music)
But instead of lighter fluid, we add a dusting
of ancient chemistry, potassium nitrate.
(upbeat music)
In the 13th Century, it was known as Chinese snow,
a key ingredient of gunpowder and fireworks.
KNO3 makes charcoal easy to ignite
and as it burns it releases oxygen fueling the fire.
At 2,500 degrees, tiny grains of silicon
melt into super hot pellets of glass
that spatter and ignite other flammables in the midst
like potassium chlorate which makes smoke.
But it's also dangerously explosive
if conditions get too acidic.
(enthusiastic music)
That's where magnesium carbonate comes in.
The same stuff you find in fire extinguishers.
(soaring music)
It neutralizes acid, keeping the whole thing
from turning into a bomb.
So instead of blowing up, all that sound and fury
activates o-chlorobenzalmalononitrile,
the lachrymator, or tear producer.
It's a king of irritants attacking the mucus membranes
of your ears, nose, and lungs, making you cough,
choke, and go temporarily blind.
It would be deadly at concentrations
more than 6,000 times greater.
(energetic music)
(snapping music)
[Narrator] Feeling Wired yet?
Subscribe.