Here is a naive view of the heisenberg uncertainty principle regarding momentum and
position. The particle's behavior is like that of a wave. The particle's momentum is
given by h over the particle's wavelength.
If the particle wavefunction is a perfect sinusoid extending over all space, the particle
wavefunction is perfect and its momentum is precisely known. But the particle could be
anywhere. delta-p is zero and delta-x is infinite.
If we wanted to be able to say the particle was in a region delta-x and could magically
reduce its wavefunction to zero outside delta-x, we would be sacrificing some
knowledge of its momentum. This is because its wavefunction over all space would now
contain additional fourier components and its wavelength would not be as well known.
If we try to make delta-x very small, all that remains of the wave function is a tiny
section which will look like a straight line inside the region of delta-x. Now our
knowledge of the wavelength and momentum disappears as we increase our knowledge
of its position.
Mike
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Mike Moloney http://www.rose-hulman.edu/~moloney
moloney@nextwork.rose-hulman.edu
Dept of Physics & Applied Optics (812) 877 8302
Rose-Hulman Institute of Technology Terre Haute, IN 47803