Lipstick Cases I

Make up table with two lipsticks and two small decorative boxes

What are LEDs?

The light of the torches in lipstick cases is produced by LEDs (“light-emitting diode”) that you also find in screens.

How do LEDs work?

Diagramm showing process of light emission by an electron — Emission occurs when the electron falls from an excited (high energy) to the ground, or in general, a lower energy level. Image source: Science Pavilion UZH

Electrons inside atoms can only sit at certain energy levels – this is a quantum principle. LEDs work by first giving energy to the electron, who jumps to a higher energy level. When the electron later loses energy, it falls down to a lower energy level. This energy difference is emitted as a photon: light is energy. The colour of that light depends on the gaps between the two energy levels: for example, a blue photon is much more energetic than a red one. This means that LEDs of different colours are made with different materials, picked for their energy gaps, and also that a red LED light consumes less energy than a blue one!