Re: Quantum Mechanics

From: Loren Haarsma (
Date: Mon Apr 16 2001 - 16:09:29 EDT

  • Next message: James W Stark: "Re: The Future of Evolution"

    On Mon, 16 Apr 2001, John W Burgeson wrote:

    > I've been asked to explain QM in 15 minutes to a seminary class Thursday
    > beginning with Aspect's experiment in the early 80s as reported in NATURE
    > on page 671 of an unidentified issue in about 1985 or so (the prof had a
    > copy which interests him).

    If you're going to talk about the spooky consequences of QM, it might be
    a good idea to spend 2 or 3 minutes to motivate QM -- how it solves some
    problems of classical physics.

    E.g. According to classical physics, if you have an electromagnetic field
    of frequency "f", you can add or absorb any amount of energy you want from
    it. According to QM, energy must be added or absorbed in quanta of E=h*f.
    (This is a good thing. Otherwise, under classical physics, a finite box
    at a finite temperature would have an infinite amount of electromagnetic
    energy inside it.)

    E.g. According to classical physics, an electron oribiting a nucleus in an
    atom should radiate away its energy, and thereby destroy the atom, in a
    fraction of a second. According to QM, there are stable bound electron
    states where the electron has angular momentum L = n*h, where n = some
    integer. (Obviously, this is a good thing.)

    E.g. QM explains why some electrons in electrical conductors are free to
    move from atom to atom. (This is a good thing if you want to build
    electric circuits.)

    And it also might be worth mentioning the correspondence principle -- that
    QM gives the same predictions as classical mechanics for "everyday"


    Have fun explaining the "spooky" stuff.... :-)

    Loren Haarsma

    This archive was generated by hypermail 2b29 : Mon Apr 16 2001 - 16:09:35 EDT