Will you please explain "Quantum" to me?

Question

What exactly does it mean? (Please..keep it simple.) Thanks!

Answer 1

A quantum is most simply described as the smallest discrete amount of a quantity you can have. What "discrete" means is that you've divided down to an amount that can't be divided anymore, so that now you're dealing with numbers of particles or "packets" of the same unit quantity. For example, suppose you had a huge amount of ping-pong balls all glued together in one big glob. If you measure the mass of the glob, you'll always find it is a whole number multiple of the mass of one ping-pong ball (let's ignore the glue for sake of illustration). For example, the glob may weigh the same as 2000 ping-pong balls, or maybe 1377 or 4250 or 3141 ping-pong balls, but it is always a whole number, never a fractional one. You can break that big glob of ping-pong balls apart in any number of ways, but each piece will also have a mass that is a whole multiple of one ping pong ball mass. The ping-pong ball can be considered a "quantum" of the larger glob. This is just an analogy, because quantum particles are on the atomic size scale, nothing so large as a ping-pong ball that we can actually see.

This idea is what brought Democritus of Abdera way back in 450 BC to propose the idea of an atom as a "quantum" of mass based on philosophical reasoning. Of course he didn't use the terminology of quantum, but the idea was similar. Roughly 20 centuries later, Albert Einstein proposed the existence of the photon as a quantum of light based on experiment and theory. Hypothetically, if you could divide up a light beam fine enough you'll find that eventually you get down to a single photon that you cannot divide anymore.

Quantum mechanics deals specifically with quantum particles, and you might hear a quantum physicist talking about the quantum particle itself or a wave equation which predicts the probability of finding a quantum particle in a certain location.

You should have asked this question in the Science & Mathematics > Physics category, that's where you'll find the most qualified people to answer this question.

Answer 2

It's a type of leap best performed by a Scottish backula.

Answer 3

Simply stated, a quantum can be described as the most minute quantity of energy physically possible. This quantity cannot be divided any further. In physics this term is related to descriptions of energy from a particle standpoint.  For example, lights unit of quantum is the photon.

Answer 4

Zach is right.  and it's related to both energy and momentum of elementry particles of matter.

the fundemental notion that a physical property may be quantized (= that the magnitude can only take on certain numerical values, rather than any value, at least within a range)

the most basic framework they have for understanding and describing nature at the infinitely small level

Answer 5

a distinct quantity of energy correspanding to that involved in the absorption or emission of energy by an atom.