Why Fireworks Are all About STEM
Bonfire Night is approaching and maybe you’re going to see a fireworks display. There’s something about fireworks that delights us, no matter how old we are. But while you’re admiring the flashes, bangs, and pretty colours, think about the fact that fireworks are teaching us principles of physics and chemistry. Yes, STEM never stops, even on Bonfire Night!
The anatomy of a firework
Most of the fireworks that shoot up into the air like rockets have these parts:
A stick or ‘tail’
You’ll notice a wooden/plastic stick that comes out of the bottom of the firework. This is an important part because it makes the firework shoot up in a straight line, rather than just flying anywhere and hurting someone. It also helps you fire them off with precision, like if you want to set a few off in succession and have a blend of lovely colours.
This gets the firework burning and ignites other fuses that produce those extra colours and little explosions you see. In the fireworks you have at home, the fuse is usually made from paper or material, and in the fireworks you see at big displays, the fuses are lit when an electric current runs along a wire to a fusehead, then ignites the fuse.
This is what lifts the firework into the sky in spectacular style. It’s usually made of gunpowder, which consists of potassium nitrate and other chemicals. The charge does not cause the explosion, it just gives your fireworks lift-off.
This is what causes the pretty stuff to happening that makes you go ‘ooh’ and ‘aah.’ A firework can have one effects or several, housed in different compartments, which ignite in sequence. Effects are made from fine explosive material which produces colourful explosions of either stars or other smaller fireworks to create an amazing spectacle.
As you can probably guess, this is the top of the firework which contains the effect(s). Sometimes the head will be pointed to make it faster.
What fireworks teach us about chemistry
When a firework goes off, it’s because chemical reactions are happening. When you light the fuse, the heat causes the chemicals inside of the firework to combust and give off smoke and carbon dioxide, carbon monoxide, and nitrogen.
Chemistry is also responsible for the gorgeous colours you see in the sky. The colours come from the burning of the metal salts inside of the firework. Different metal salts produce different colours when they burn. Sodium creates yellow and orange, copper and barium give off green or blue, and calcium or strontium produces red.
What fireworks teach us about physics
Physics is behind the principle that the chemical energy inside of fireworks is converted into different types of energy when the firework is ignited, such as heat, light, sound, and kinetic energy. (movement)
When a firework shoots off into the air, this is a principle of physics. No doubt at some time in your life, you came across Newton’s Law of Motion; ‘Every action has an equal and opposite reaction.’ So when the gunpowder in the charge is ignited and starts to burn, it gives off gases that fire backward and cause the opposite reaction of propelling the firework forwards and into the air.
So if you’re going to a firework display this year, or you’re having your own at home, now you know that the pretty colours and loud explosions you see are all down to science. Who said STEM was dull?
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