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Explosions all go bang, but they’re not all the same. We’ll check into how and why. Today, on Engineering Works!

We’ve had explosives a long time — gunpowder, dynamite and TNT. Plastic explosives. They cause death and destruction in the wrong hands. But engineers do good things with explosives, too — move the landscape around for highways, bridges and big buildings; demolish old buildings cheaper than tearing them down by hand.

Most explosives get their power from burning. That’s all an explosion is – gas produced by burning, really fast burning. And you get a lot of gas, very quickly. It’s the pressure from that gas that blows things apart. How much gas is produced how fast determines how powerful an explosive is. Plastic explosive is more powerful than gunpowder because it burns – and produces its gas – a lot faster.

Instead of burning, some explosives produce gas by breaking down complex molecules into simpler molecules that just happen to be gases. They produce only enough heat to continue chemical reactions that produce gas like ordinary explosions.

One explosive – triacetone triperoxide – breaks down into oxygen and ozone instead of burning. It’s very destructive because this breakdown produces a lot of these gases in the blink of an eye.

Engineers use explosives like these to save lives, too. They use one called azide to produce the gas that inflates the airbag in your car when you hit something hard.
It’s time for us to explode on out of here. See you later.

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