Hydrogen Atom and Spectra: free physics simulation
Kick the electron up the energy levels and watch it fall back, giving out light of exact colours.
▶ Open the simulationFree, no sign-up. Works on phones, tablets and laptops.
The science
In the Bohr model the electron in a hydrogen atom can only have certain energies, Eₙ = −13.6/n² eV. When it falls from a higher level to a lower one it gives out a single photon whose energy equals the gap, so hydrogen glows at a few exact wavelengths: its emission spectrum. Falls to level 2 give the visible Balmer lines (656, 486, 434 and 410 nm); falls to level 1 give ultraviolet Lyman lines.
Eₙ = −13.6 / n² eV, E(photon) = Eᵢ − E_f
Things to try
- Lift the electron to level 3 and let it fall to 2 to make the red 656 nm line.
- Turn on “heat the gas” and build up the whole spectrum.
- Ionise the atom by giving it 13.6 eV.
Topics covered
bohr model energy levels emission spectrum absorption photon balmer lyman quantum electron
How to use it
Open the simulation, then change the experiment live with the sliders, checkboxes and buttons in the side panel. Drag objects on screen where it makes sense, and use Pause, Step, Speed and Reset in the bottom bar to study every moment.
Frequently asked questions
What does the Hydrogen Atom and Spectra simulation show?
In the Bohr model the electron in a hydrogen atom can only have certain energies, Eₙ = −13.6/n² eV. When it falls from a higher level to a lower one it gives out a single photon whose energy equals the gap, so hydrogen glows at a few exact wavelengths: its emission spectrum. Falls to level 2 give the visible Balmer lines (656, 486, 434 and 410 nm); falls to level 1 give ultraviolet Lyman lines.
What is the key equation?
Eₙ = −13.6 / n² eV, E(photon) = Eᵢ − E_f
Is the Hydrogen Atom and Spectra simulation free?
Yes. It runs free in any web browser on phones, tablets and laptops, with no sign-up or download.
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