Quantum Physics: fun facts and quiz

Quantum physics describes atoms and the particles inside them. At that scale, things behave in ways that seem impossible in everyday life.

Key fact
Quantum physics makes lasers, LEDs and computer chips possible.

In 1900, Max Planck found that energy comes in tiny fixed packets, called quanta. Light, too, arrives in packets, called photons.

Key fact
Einstein won his Nobel Prize for explaining light as photons.

Light and electrons behave both like waves and like particles. In the famous double-slit experiment, single electrons build up a wave-like pattern.

Key fact
This double nature is called wave–particle duality.

Heisenberg’s uncertainty principle says you can’t know a particle’s exact position and exact momentum at the same time. The more precise one is, the fuzzier the other.

Key fact
Werner Heisenberg published it in 1927.

Before it’s measured, a quantum particle can be in a mix of possible states at once, called superposition. Measuring it gives one definite result.

Key fact
Schrödinger’s cat is a thought experiment about this idea.

Entangled particles are linked: measuring one instantly tells you about the other, however far apart they are. Einstein called it “spooky action at a distance”.

Key fact
The 2022 Nobel Prize in Physics went to experiments on entanglement.

Quantum computers use qubits, which can be in superpositions, to tackle certain problems far faster than ordinary computers. They’re still experimental and fragile.

Key fact
Many qubits must be kept colder than outer space.