This lecture covers selected parts of sections 1-11 through 1-14 of McQuarrie:
In an experiment in class, we observed individual photons by the pulses of electrons they produced in a photomultiplier tube. de Broglie, reasoning from the known wave-particle duality of light, extended Einsteins formula for the momentum of a photon in terms of its wavelength. He argued that the characterstic wavelength of a particle of momentum p was lam = h/p.
de Broglie waves were observed experimentally by the electron diffraction patterns they produced when electron beams were impinged on polycrystalline metal foils. The wavelike properties of electrons are used in the electron microscope to produce images of far higher resolution than the optical microscope.
The Uncertainty Principle of Heisenberg states that if we wish to locate any particle to within a distance Dx, then we inevitably introduce an uncertainty Dp in the momentum of the particle. One can also express the uncertainty principle in terms of energy and time. For example, the longer one spends measuring the energy of a system, the more certain the value becomes. Another consequence of the uncertainty principle is that the very act of measuring a system perturbs it. One of the goals of instrumentation science is to develop methods that disturb the system under study negligibly.