Quantum physics and quantum mechanics are the same thing and its principles have helped to invent computers, photodetectors in digital cameras, light emitting diodes, lasers and nuclear power.
Quantum physics describes the smallest things in our universe, such as molecules, atoms and subatomic particles (electrons, protons and neutrons).
Quantum physics describes how the universe is actually working: It’s waves. But it’s not like a physical wave, such as a water or sound wave.
A quantum wave is an abstract mathematical description which helps to understand it, such as where a particle may be.
Quantum physics involves predicting that things will happen with probabilities, which is a departure from the clockwork, deterministic universe in classical physics.
However, no one has ever seen a quantum wave because whenever we measure an electron all we see is a point-like electron particle.
So there’s the quantum realm where waves exist and the world we can see, which is where the waves have turned into particles.
Superposition means adding together waves. One example is visible when dropping two pebbles in a pond where the ripples overlap.
Entanglement refers to electrons that are inextricably linked, even if they move far away from each other. A measurement of one particle, such as whether it’s spin is up or down, is now correlated with a measurement on the other. Somehow there is a link between the electrons that stretches over great distance.
Quantum tunnelling is where particles have a probability of moving through barriers, essentially allowing things like electrons to pass through walls.