Electron energy0 eVExcited atoms0Photons emitted0Strongest line—Detector rate0 /s
Atomic Emission Lab

Follow the particles

Electron
Excited atom
Photon

Choose an experiment

Emission controls

45 V
45 Pa
300 K
1.4 s

Live measurements

Electron energy45 eV
Excited fraction0%
Photon count0
Strongest line—

Object focus

Tap an electron, gas atom, photon, grating, or detector for a short explanation and tracking view.

Detected photons over time

View and timing

1.00×
1×

Teacher demonstration tools

Electron collisions supply discrete excitation energies. When excited states decay, atoms emit photons whose energies equal level differences. The resulting line spectrum identifies the element.

Voice and language

0.92×

What to watch on the canvas

Start the lecture. Each spoken idea activates a matching arrow, glow, close-up, or particle process on the apparatus.

10 sequential chapters and scripts

Learning objectives

  • Explain how collisions excite atoms.
  • Connect electron transitions with photon energy.
  • Relate wavelength to visible color.
  • Interpret a discrete line spectrum.
  • Use spectral lines to identify an element.

Key concepts

Atoms have discrete allowed energies. An energetic collision can lift an electron to a higher state. When it returns to a lower state, the energy difference leaves as a photon. Many identical atoms create characteristic bright spectral lines.

Suggested experiments

  • Increase voltage from zero and identify the excitation threshold.
  • Change pressure and observe the collision rate.
  • Compare hydrogen, sodium, neon, helium, and mercury.
  • Use slow speed and Step Forward to follow one event.

Important limitation

This is a scientifically grounded educational model. Collision probabilities and apparatus scale are simplified, while line wavelengths use representative measured emission lines.

Atomic emission assessment — 7 questions