Lesson 1 — What Does “Quantum” Mean?
What Does “Quantum” Mean?
The word quantum comes from Latin and means “how much” or “an amount.” In Quantum Physics, it denotes a definite, discrete amount of a physical entity.
What does “discrete” mean?
It means that, in certain cases, nature does not permit every intermediate value.
It is like climbing a staircase: we may stand on one step or on the next, but not in the air between them.
The photon
A characteristic example is the photon. A photon is a quantum of electromagnetic radiation — a complete packet emitted or absorbed as a unit.
We do not detect half a photon.
Photons, however, do not all have the same energy; their energy depends on their frequency.
Quantum theory does not tell us that the whole of nature moves to a single, hidden metronome.
It reveals something subtler and stranger: certain physical quantities are exchanged in discrete packets and do not always vary in the continuous way our senses lead us to expect.
Keep this in mind:
In the quantum world, nature does not always give us
an unbroken line. Sometimes, it gives us steps.
And the first step towards the invisible is to recognise that between two steps there may be nowhere at all for us to stand.
