Quantum Physics Questions

[JacobEvans]

Okay, I want to learn about quantum physics, but I'm rather limited by my lack of understanding of some of the principle ideas.

First question I think I should ask, What's a Quanta?

I've read a bunch of descriptions of it, but I can't understand them for the life of me. Please, for the love of all that is good, if you have a diagram or picture that you think might help me understand what you're saying, put it in! :lol:

Thanks in advance!

 

[Spase]

I'm by no means the person who should be talking about quantum physics but I think I can answer your basic question..

The word quantum refers to the idea that on very small scales energy states are quantized, not continuous. This means they have specific levels they can occupy rather than a spectrum. It's the difference between the set of integers and the set of real numbers. With integers you're either at 1 or 2 for 42 or whatever. With the real numbers there is an infinite number of places between these states. A simpler example may be the difference between a volume knob that increases volume continuously and a digital stereo that shows the volume as a number.

An example of this is the energy states that electrons can occupy in different elements. In a given element an electron occupying a specific orbital will increase in energy if it's excited by something but for a given orbital in a given element/atom there are only very specific levels the electron can jump to. It cannot absorb an amount of energy that would put it between two of it's possible energy states. This is an example of quantization because there is a specific set of states that the electron may have without any intermediate possibilities.

The example that's usually given in classes is Einstein's experiments with the photoelectric effect. Different wavelengths of light are more energetic than others. The photoelectric effect is the phenomenon where by electromagnetic radiation (light) is directed at a material which then, depending on the wavelength of the light, will, or will not lose electrons which are essentially knocked off the material. This is interesting because electrons being knocked off is not a function of how much energy was directed at the object but only of how energetic individual photons were. For example, a brighter light puts out more total energy but each individual photon does not have enough energy to displace an electron.

I'm linking the wikipedia description of what Einstein did with the photoelectric effect because it's late.. and I worry that I just wrote you a lot of gibberish:
http://en.wikipedia.org/wiki/Photoelectric_effect#Einstein:_light_quanta

I hope that this has been at least a little helpful. There's a lot of reading you can do online about this stuff but I figured since you said you'd tried and wanted the basic explanation of 'quanta' I figured I'd at least try. Good luck!

Oh, and my other caveat: I don't know physics. My perspective on the subject comes from chemistry for the most part.

Peace.

 

[JacobEvans]

Thank you SO much.
That makes so much more sense.

That clears up a lot of things.