eodtalley
1761
19
2
This is a tube from the Franck-Hertz experiment. It isn't pretty but inside of it mercury has been vaporized. That little glowing bit is exciting electrons through the mercury to make'em crash.
Same thing different angle.
The whole thing is set up in this cobbled together looking rack of metal, keeps all the bits together.
I am very precise about my measurements. The experiment from 1914 was the first thing to demonstrate the quantum nature of atoms. Sounds cool but the short version is that electrons have very specific and predictable energy levels.