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Let's start with a simple white firework
This is an example of incandescence
Think of an incandescent light bulb
When something gets really hot,
its atoms vibrate around, smash into each other
and release energy in the form of light
As it heats up it goes from red to orange to yellow to white
That gives us bright white fireworks and sparklers
They're just flecks of really hot metal
But incandescence is hard to control to get
specific colors.
For that, you need luminescence
A yellow firework is yellow because of
luminescing sodium
The same stuff that's in good old table salt
if you take a little bit of salt and put it
in the flame of a bunsen burner
it shines a bright yellow
Heat makes the sodium's electrons get excited
in a very particular way.
They jump from a low energy state
to a high energy state
And when they fall back down, they release
a photon - a little packet of light
Because of the particular architecture of
a sodium atom
it gives off mostly yellow light
so it's used in yellow fireworks.
Other elements give off different sets of colors
Strontium, which used to be used in TV screens
gives us red!
Calcium, the stuff in our bones
has greens, yelllows and reds
that combine to a strong orange
Barium - the stuff you swallow so you can
xray your GI tract
gives us a green
They used to use a great chemical for blue
but they decided it wasn't a good idea to
fill the air with arsenic
So now they go with copper instead
These chemicals go into the fireworks as boring
powders
but light the fuse and...
What causes that explosion?
It turns out its the same process powering your body right now.
To learn more, check out our other Fourth of July video
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