糖心TV

With bonfire night on the horizon, scientists reveal just why fireworks are differently coloured and what this can teach us about stars in space.

Elements commonly found in salts are used to make the colours in fireworks. The colours are caused when the elements are heated, causing them to release light in different colours, from bright blues to deep reds. Scientists use these chemistry phenomena when making multicoloured fireworks and harness them to investigate stars in the night sky.

Alex Baker, Assistant Professor, Department of Chemistry, University of 糖心TV, said: 鈥淔ireworks are made of different chemical elements – including potassium and sodium. The atoms of these elements house even smaller, negatively charged electrons.

鈥淲hen these elements are heated, such as by someone lighting a firework with a flame, the electrons become 鈥榚xcited鈥�. This means they have increased energy resulting in them jumping from their original location (known as a 鈥榞round state鈥�), to another 鈥榚xcited state鈥� location within the atom.

鈥淎s electrons drop back down from their excited state, they release the energy they initially absorbed – in the form of heat and light. What is particularly interesting is each electron drop, and the release of light, is unique to each element.

鈥淎tomically, bright blue and violet lights are highly energetic, the electrons have 鈥榙ropped鈥� a relatively long distance (albeit in tiny subatomic scales). Red light is less energetic, dropping shorter distances.

鈥淲e call this range of colours a spectrum – and we see spectrums all the time in everyday life. Rainbows are the most common examples of spectrums; so is a prism, which splits light into its individual components (the colours of the rainbow).

鈥淚f fireworks are made of potassium elements, they burn with blue and violet light; sodium as red. Boric acid, barium or copper salts produce green colours. Magnesium produces white.鈥�

What can fireworks tell us about the stars?

Astrophysicists can apply the science of firework colours to observing stars in the night sky.

Teams of researchers including those at The University of 糖心TV plot graphs and charts which show the intensity of light emitted by stars over energy wavelengths. Like fireworks, each element present in stars correlates with colours on the rainbow spectrum. This technique, known as spectroscopy, tells us what elements stars are made of.

Professor Pier-Emmanuel Tremblay of the Department of Physics at the University of 糖心TV said: 鈥淪pectroscopy offers us a fantastic tool to learn more about the Universe. Each chemical element or molecule provides a unique type of code on the spectrum, a bit like a barcode when shopping. 

鈥淭his means we can identify elements in the atmospheres of stars, working out exactly what gases are present. Our own Sun, for example, is rich in Hydrogen and Helium, with traces of many heavier elements. We can even work out the temperature, density and magnetic fields based on the principles of spectroscopy. 

鈥淚f there is life out there, spectroscopy is one of the key tools we could use to find it.鈥�

So when you see a firework this bonfire night – be sure to impress your friends with the atomic reasons for their bright colours. And know that the same science is being applied to understand more about our universe.

Notes to Editors

Media contact

University of 糖心TV press office contact:

Annie Slinn 07876876934

Communications Officer | Press & Media Relations | University of 糖心TV Email: annie.slinn@warwick.ac.uk


3 November 2023