Atomic Energy Levels Simulator
Discover how the vibrant colors of neon lights and faraway stars are created by electrons jumping down quantum staircases.
About this simulation
- What
- An interactive Physics simulation of Atomic Energy Levels Simulator.
- Who
- Designed for AP, IB, and A‑Level Physics students.
- How
- Runs in any modern browser — drag, adjust, and explore in real time.
Updated 2026-03-22
Key Concepts
Quantized Energy ($E_n$)
In an atom, electrons can't just be anywhere. They must exist in very specific, fixed 'energy levels' (like steps on a ladder). The lowest is $n=1$ (Ground State).
Photon Emission ($E=\Delta E$)
When an electron drops from a higher level to a lower level, it sheds the extra energy by spitting out a single photon (a particle of light).
Spectral Lines
Because the energy steps are precisely fixed, the photons emitted will always have exactly the same energies (colors). This creates a unique 'barcode' (spectrum) for every element.
The Quantum Staircase
For centuries, scientists wondered why heating up different gases produced light of very specific, pure colors, rather than a continuous rainbow. Niels Bohr solved this by proposing the quantum model of the atom.
In this simulator, you control the single electron of a Hydrogen atom. Grab the electron and pull it up to an 'Excited State' ($n > 1$). This requires adding energy. But the electron doesn't like being up there. It will want to fall back down.
Drag the electron from a high level down to a lower level. The energy difference ($\Delta E = E_{high} - E_{low}$) is instantly converted into a photon! If you drop to $n=2$, the energy matches visible light (the glowing Balmer Series). Drops to $n=1$ are huge, creating invisible Ultraviolet light.