Quantum computers store data in qubits, short for quantum bits.

A qubit can be made with a single atom. Electrons in atoms have poles, like the magnetic North and South Poles. An electron’s poles can be oriented in one of two directions - either “spin up” or “spin down”. An electron’s polarity is determined by its energy state. Changing the energy state can flip the orientation.

The up-or-down orientation of the polarity of an electron is used to indicate zero or one. Thus, qubits can store information.

At room temperature, the energy in the environment cause the spin to bounce randomly back and forth between the up and down states. So qubits are cooled to almost absolute zero to keep them in the spin-down, their lowest energy state, until they are set by adding precisely tuned microwave energy.

When observed, a qubit’s electon’s orientation will either be spin-up or spin-down. Prior to observation, a quibit has a certain probability (percent liklihood) of being zero or one - this is a bit like Schrödinger’s cat. These probabilities (that add up to one) are refered to as the particle’s “super position”.

Source: https://www.youtube.com/watch?v=zNzzGgr2mhk - feat. Prof. Andrea Morello. I would listen to Prof. Morello read the phone book.