That Darn Quantum Mechanics again....

Here is a cool introduction to the bizarre world of Quantum Mechanics. It is a paraphrase of the opening chapter to "The Feynman Lectures in Physics" Book 3. It is a very plain and very simple demonstration of what we were up against in the 1930's, and it is EXCELLENT.



However, it lacks in two areas:

1. It does not mention that any wave effect (waves or electrons) is only possible if the wavelength of the "waving" is about the same size as the aperture. (simple wave theory)

2. It does not say why looking at the electron affects the pattern. The reason why is that until you look, there is an interference pattern, but if you look, you have to bounce a photon off the electron back into your eye to see it. This photon has momentum according to p = E/c, and although tiny, is just enough to push the electron off course from the interference pattern. If you lower the "wiggling" (the frequency) of the light so that this effect becomes less, the amount of photon momentum needed to tell which slit the photon has gone through is enough to not destroy the pattern, but the light is so dim, it is too dark to see which slit it has gone through. This reciprocal effect has a name , and it is the Heisenberg Uncertainty Principle.