The deadly irony of gunpowder - Eric Rosado

3,055,371 views ・ 2013-11-04

TED-Ed


Please double-click on the English subtitles below to play the video.

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Everybody loves fireworks --
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the lights, the colors,
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and, of course, the big boom.
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But the history of fireworks
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isn't all hugs and celebrations.
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Long before epic fireworks displays,
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chemists in China invented the key ingredient
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that propels those bright lights into the sky.
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That invention was what we now call gunpowder.
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Our story begins back in ancient China
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in the mid-ninth century
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where early Chinese alchemists
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were trying to create a potion for immortality.
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Instead, what they created was a flammable powder
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that burned down many of their homes.
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They quickly realized that this black powder,
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which they called fire medicine,
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was precisely the opposite of something
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that would make you live forever.
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In these early days,
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the Chinese hadn't yet figured out
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how to make the powder explode;
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it was simply very flammable,
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and their armies used it
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to make flaming arrows
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and even a flamethrower.
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But once they figured out the right proportions
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of ingredients to create a blast,
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they began using the powder even more,
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creating fireworks to keep evil spirits away
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and bombs to defend themselves
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against Mongol invaders.
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It was these Mongols, most likely,
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who spread the invention of gunpowder
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across the world.
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After fielding Chinese attacks,
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they learned how to produce the powder themselves
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and brought it with them
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on their conquests in Persia and India.
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William of Rubruck,
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a European ambassador to the Mongols,
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was likely responsible for bringing gunpowder
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back to Europe around 1254.
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From there, engineers and military inventors
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created all kinds of destructive weapons.
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From bombs to guns to cannons,
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gunpowder left its mark on the world
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in some pretty terrible ways,
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in contrast to the beautiful marks
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it can leave in the air.
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So, how does black powder propel
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fireworks into the sky?
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You might have seen old Westerns or cartoons
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where a trail of gunpowder is lit
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and it leads to a large and obviously explosive barrel.
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Once the fire gets to the barrel,
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a large boom occurs.
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But why doesn't the trail itself explode?
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The reason is that burning the powder
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releases energy and gases.
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While the trail is burning,
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these are easily released into the surrounding air.
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But when the gunpowder
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is contained within the barrel,
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the energy and gases cannot easily escape
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and build up until
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BOOM!
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Firework canisters provide
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a single, upward-facing outlet
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to channel this explosive energy.
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The wick ignites the gunpowder
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and the energy takes
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the easiest exit from the canister,
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launching the firework high into the sky.
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The flame then makes its way
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through the firework's encasing
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and the same reaction occurs
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high above our heads.
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So, while the Chinese alchemists
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never found the compound for eternal life,
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they did find something
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that would go on to shape all of civilization,
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something that has caused
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many tragic moments in human history,
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and yet still gives us hope
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when we look up in celebration
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at the colorful night sky.
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