What is Spectroscopy?
Spectroscopy is the study of colour and light. Every colour we see is a result of light being emitted or reflected by atoms. More specifically, it all comes down to electrons — the tiny, charged particles that move around the centre of an atom. When these electrons absorb energy, they get “excited” and jump to a higher energy level. But they can’t stay there for long. When they fall back to their original level, they release energy as a photon — a small burst of light.
The amount of energy released determines the colour of that light. A small drop in energy might release a low-energy photon that would appear red to our eyes. A bigger drop in energy gives off a higher energy photon that might look blue or violet, or even ultraviolet, and thus invisible. This process, called atomic emission, is how neon lights glow, why fire changes colour with different materials, and why stars shine in the way they do.
Each Element Has Its Own Colour Signature
Every type of atom has a unique structure. This means each element emits photons of specific energies — and therefore specific colours — when its electrons are energised. When we pass this light through a prism or special filter, we can split it into a spectrum of colours, a bit like a rainbow. This spectrum acts like a barcode for the element: hydrogen has one pattern, oxygen another, sodium another still.
This is more than just pretty science — it’s a powerful tool for discovery. It means we can work out what something is made of just by analysing the light it emits.
Looking Into the Stars
Astronomers use this exact principle when studying distant stars, galaxies and planets. Even though we can’t touch these faraway objects, we can collect the light they emit or reflect and break it down into a spectrum. By looking at which wavelengths are present — and which are missing — scientists can tell what elements are there.
This technique called spectroscopy has helped us learn that stars are mostly hydrogen and helium, that certain exoplanets may have atmospheres rich in water vapour or methane, and that distant galaxies contain the same elements we find here on Earth. All of this knowledge comes from watching how energised electrons emit photons — tiny messengers of colour and information.
Why Spectroscopy Matters for Our Children
For children learning science, it’s powerful to understand that light is not just something we see — it’s something we can read. It carries clues about the universe, about life, and even about their own bodies. Melanin, and specifically eumelanin absorbs and interacts with photons across a wide range of energies — showing that we are not just passive in the face of light, but deeply connected to it.
Knowing how colour and light reveal the truth of what things are made of can spark curiosity, critical thinking and a deep sense of wonder. Our children are surrounded by light — and now they’ll know how to decode it.
