1. Franck-Hertz experiment with Neon
Weifeng Su

2. Principles： Bohr model of the atom:
electron
Bohr model of the atom:
The electrons can only travel in specific orbits: at a certain discrete set of distances from the nucleus with specific energies.
The electrons do not continuously lose energy as they travel, instead, at constant energy.
They can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency , determined by the energy difference of the levels according to Bohr's formula h =ΔE, where h is Planck's constant.
orbit
nucleus

3. Principles：
Elastic collisions Inelastic collisions First excitation state First excitation potential v

5. I-U curve
Ammeter range
Enough data
2 peaks 2 troughs