An electrifying lesson

While much of chemistry can be explained to students using classical experiments, there’s no way to authentically visualise electrons transitioning between energy levels. Flame tests provide evidence through line spectra but this demonstration using LEDs offers an even simpler way to demonstrate this complex idea. The experiment is adapted from a classic physics A-level experiment.

Within the LED there’s an energy barrier similar to the energy levels in atoms – an electron requires a minimum amount of energy to overcome it. As electrons cross the barrier, a photon of light is released of a frequency proportional to the size of the energy barrier. With this we can model atomic emissions (although the energy levels in the solid actually have a band structure).