This month we’ll be changing the clocks, and the by the end of it the darker evenings will bring with them the smell of smoke and jacket potatoes eaten outdoors, the whump and whizz of fireworks and the collective sighs of thousands at bright lights in the sky. Bonfire Night will have arrived.
But how much do we know about where fireworks came from and what makes them work? Let’s take a look at firework fact and folklore…
Who…
…invented fireworks? The Chinese invented gunpowder almost by accident during experiments with saltpetre (potassium nitrate) in a search for immortality. Fireworks started with one particularly curious Chinese monk called Li Tian, more than 1,000 years ago. Wishing to scare away ghosts, he stuffed gunpowder into a length of bamboo, and threw it into the fire. It went off with a loud bang and a puff of smoke. History doesn’t record if the same thing happened to his eyebrows, but fireworks had been born.
What…
… makes them work? Controlled burning of chemicals in confined spaces – or to, put it another way, explosions. The blue touch-paper is the main fuse. For a firework that’s to be blasted into the air before releasing its colourful starburst, the main fuse lights two others – one which burns quickly and ignites the charge which shoots the firework skywards; and one which burns more slowly, timed to ignite the chemical starburst just as the firework reaches its highest point.
Why…
…are fireworks different colours? And why do we see them before we hear them? Chemistry answers the first question; physics the second. Fireworks involve burning particular chemicals at temperatures of up to 2,000 degrees. Different chemicals burn with different coloured flames. Calcium salts have an orange flame, strontium and lithium are red, copper is blue, and sodium yellow. Silver comes from burning aluminium, titanium or magnesium. (Early photographers lit magnesium as a primitive ‘flashgun’.) We see the light and hear the sound at different times because light travels at almost 300 million metres a second, but sound at only about 350 metres a second, so we see the flash before we hear the bang.
Where…
…did it all start? Under the Houses of Parliament in 1605. A group of Catholics wanted to overthrow King James, who was fiercely anti-Catholic, and planned to blow up not only him, but everyone in Parliament. The intention was to replace him with his daughter Elizabeth. It was an ill-conceived plot. The blast would have killed numerous Catholics too. A clumsy attempt was made to warn high-profile Catholics, resulting in a search of the Parliamentary cellars that revealed 36 barrels of gunpowder and explosives expert Guy Fawkes. The plot had unravelled. After torture, Fawkes gave up his fellow conspirators, and all were eventually killed, some shot whilst fleeing, other executed. King James ordered bonfires on November 5th to celebrate his survival.
When…
… can I let fireworks off? Any time you like, so long as it’s not after 11pm, when it becomes illegal. And you won’t be able to buy any after November 13th, which is the point at which they’ll no longer be available in the shops.
How…
… to make it safe? Lots of advice already exists on the net, for retailers, for display organisers, and for children. It’s all good advice, and we’d urge you to heed it, especially as the event’s likely to be drawn out this year, with November 5th falling on a Wednesday. Please stay safe.
