The hills are alive with the sound of oooh and ahhh and a lot of flashing and banging! It is that time of year again when we all get sore necks from staring up into the sky at the beautiful fountains of colour we call fireworks.

As someone who has a weakness for sparkly things and making explosions, fireworks make me excited! Even more so when I start to think about the chemistry involved (I know, I am truly sad!).

Our desire to mix things together and see what happens is as old as humankind. We regularly do chemistry in our kitchens, gardens and even in the shower.

In fact many of the best chemical reactions were discovered by accident. Fireworks are no exception, with the first record of “bursting bamboo” around 200BC. Bamboo grows so quickly that pockets of air and sap are trapped along the inner stem.

When a Chinese person, whose name history has forgotten, was running low on wood for burning they threw some bits of bamboo on the fire only to get a huge shock when it exploded with an impressive bang! It wasn’t long before bursting bamboo was a regular feature at celebrations of all kinds.

The evolution of fireworks continued in China, where alchemists were trying to invent the elixir of life. While heating a potion of sulfur, saltpeter (potassium nitrate), arsenic disulfide and a dash of honey they managed to burn themselves and their shack to the ground. With a bit more experimentation Chinese alchemists had invented gunpowder.

It didn’t take long for some wise spark to stuff bamboo with this primitive gunpowder and wammo! The first proper banger!

Over time chemists have finetuned all parts of fireworks to give us the beautiful, spectacular and colourful displays we get today.

The colours come from burning metals like strontium (red), copper (blue) and magnesium (white) that are packed into little parcels called stars. These stars are arranged inside a shell in the pattern that you want the exploded firework to make in the sky.

So if you want a Valentine’s Day display you could arrange strontium stars in a heart shape inside the shell and you would get sparkly red hearts lighting up the sky Ahhhh… All this chemistry is very cool but it will be in vain if the firework can’t be set alight. This is where the fuse comes in.

You might think that it is just a bit of twisted paper that gives you time to leg it before the blast, but I want to convince you to think again. There are fuses for all sorts of occasions – remote electrical fuses are the most common used in professional pyrotechnics but some of the older ones are best. A PIC (Plastic Ignitor Cord) can carry a lit spark under water – YouTube it, it is superb and possibly one of my all time favourite science demos.

This is the one week where chemistry, banging and flashing can be normal dinner time conversation… enjoy!