Fortunately, fireworks have existed for hundreds of years. Otherwise, today’s health and safety regulations might prevent them from happening if they were invented today. Fireworks help celebrate numerous occasions, including national holidays and provide dazzling psychedelic displays of colours. From a science perspective, fireworks teach us engaging lessons in physics and chemistry.
Where can you get fireworks?
There are fireworks for sale in-person and online, but you must source them from registered sellers. In some places like Northern Ireland, a valid firework license is needed to buy, possess, and use fireworks. Therefore, it’s advised that you check local regulations in your area.
The role of chemistry
A firework explosion is essentially a lot of different chemical reactions that happen simultaneously, very quickly. Fireworks contain compacted solid chemical compounds which begin to react when heat is applied. Once the chemical reaction is underway, these chemical compounds burn with the oxygen in the air and convert into other chemicals, releasing carbon dioxide, carbon monoxide and nitrogen in the process.
Another way in which chemistry plays a role is the creation of colour. If you did chemistry experiments at school, you’ll know that there are many metals which glow with very intense colour when they’re burnt in a hot flame. The colour of fireworks comes from different metal compounds that are packed inside. Different metals give different colours. For example, sodium compounds give yellow and orange colours, while copper and barium salts give green or blue, and calcium makes red.
Each firework is designed with chemistry in mind, so it produces specific colours when lit.
The role of physics
When fireworks are lit, there are other ways the chemical energy is converted. Heat, light, sound, and kinetic energy of movement are all examples. One of the fundamental laws of physics, called the conservation of energy, states the total chemical energy packed into the firework before it ignites must be the same as the energy remaining in it after it explodes.
Another way physics can help explain fireworks is the way they shoot up into the air. Newton’s third law of motion, action-and-reaction, powers the firework’s ability to shoot. The exhaust gases are released when a firework burns fire backwards like a rocket blast. It creates a reaction force that shoots the firework into the air.
Furthermore, physics also helps explain the symmetry of firework displays. Have you ever noticed how fireworks always explode symmetrically with one part going left and another part going right? This is explained by another fundamental law of physics called conservation of momentum, which states there must be balance in the momentum of the firework before and after the explosions, which allows the explosions on either side to be balanced.
Different types of fireworks are designed and created with physics and chemistry to create other firework displays. For example, firecrackers are known for their crackles – they’re an example of how science has been used to introduce sound into their presentation.
In conclusion, fireworks are impressive displays of dazzling colour and light, but they’re also great examples of science. They’re a relatable example science teachers can use in their lessons to help explain specific theories of science and chemical reactions.