Emission Spectrum Viewer
See the coloured line spectra of hydrogen, helium, neon, sodium and more.
About the Emission Spectrum Viewer
Free emission spectrum viewer. Pick an element and see its coloured spectral lines and their wavelengths, compare with a continuous spectrum, and learn how astronomers identify elements. Built for atomic & quantum, the emission spectrum viewer runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
See the coloured line spectra of hydrogen, helium, neon, sodium and more. Use it to explore atomic & quantum ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Emission Spectrum Viewer
- Use the controls to change Element (gas discharge). The simulation reacts instantly.
- Pick an option such as Emission (bright lines), Absorption (dark lines) to switch modes or load an example.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Compare hydrogen and neon.
- Switch to Absorption.
- Hover to read wavelengths.
- Look at sodium's double line.
Key ideas you can learn
- Each element emits light at its own set of wavelengths: a fingerprint.
- Hot solids give a continuous spectrum, but hot gases give bright lines.
- Astronomers use spectral lines to work out what stars are made of.
Where this is used in the real world
Astronomers identify elements in stars from spectral lines. Forensic and mining labs use the same method to analyse samples.
Who is this simulation for?
Advanced high-school and university students in chemistry and physics, and curious learners who want to see how the atomic world behaves.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Why does every element have a different spectrum?
Each element has a unique set of electron energy levels, so the photon energies released in jumps between them are unique too.
How is this used in real life?
In spectroscopy, to identify elements in stars, in flame tests, and in analysing materials.
Is the Emission Spectrum Viewer free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Emission Spectrum Viewer work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.