How do fireworks work?

How do fireworks work?

Find out what makes fireworks go bang

Whoooooooooooooooooooosh! Bang! It can only be the sound of Bonfire Night. But how do fireworks produce exciting displays like this one?

Explosions:

Fireworks were first made in China over 1,000 years ago!  Gunpowder is what makes gunpowder explode. Potassium nitrate is the most important part of gunpowder. This is what propels the firework into the sky. A fuse is used to light the gunpowder, which ignites to send the firework skyward. Once the firework is in the air, more gunpowder inside it causes it to explode with a BANG!

Colour and sparkles:

Colours are made by burning metal salts. Did you know that if you burn table salt (sodium chloride) it makes a yellow flame?

Burning different types of metal salts makes different coloured flames. Have a look at this:

The bright sparkles in fireworks come from burning small bits of metal, such as iron or steel filings.

Firework patterns:

A firework looks like this:

Fireworks

Picture from Anatomy of a Firework, PBS

The fuse sets off a charge, which ignites the gunpowder. This propels the firework into the sky.

Once the firework is in the sky, the gunpowder within the firework ignites. This causes the 'stars', which contain metal salts and iron filings, to explode in different colours and sparkles. If the firework is in sections, the tars can be in different compartments. These compartments explode at different times, making different patterns.

The pattern of stars around the central gun powder charge creates different patterns of fireworks. For example, if the stars are in a circle around the black powder charge, you get a circle display of colour.  One mistake in the placing of the stars and the whole pattern will be ruined!

Enjoy your fireworks - now you can explain to everyone how they work.

Curriculum information

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