Category: The Uncertainty Principle

Isaac Newton realized that the laws of motion he had discovered, including the Law of Universal Gravitation, could explain, at least in principle, the behavior of all physical objects in the universe known at the time. These physical laws were so powerful they allowed scientists of the time to calculate with accuracy the movements of…

When we separated light into its constituent lines, or binned scintillation photons according to their energy, we were performing spectral analysis. Since light and gamma rays most commonly act as waves, what we have been doing is deconstructing a complex electromagnetic wave into many simple sine waves. The same method can be applied to the…

Bohr realized that if there is an uncertainty relationship between momentum p and position x: which comes from quantizing momentum as a function of wavelength: A similar uncertainty principle must then exist between energy E and time t. This is because: where frequency is the inverse of a time interval f = 1/t, so: Indeed, an identical relationship exists for the product of…

A demonstration of the Uncertainty Principle is simple to conduct using a laser pointer and an adjustable slit consisting of two razor blades. The idea is that the photons emitted by the laser travel without diverging. As shown in Figure 104, the photons exiting the laser can be assumed to have momentum only along the x axis (so py =…

In 1925, German physicist Werner Heisenberg was an assistant to Niels Bohr at the Institute of Theoretical Physics at the University of Copenhagen. Heisenberg’s research related to the development of mathematical operations to calculate the expected results of experiments on hydrogen atoms based only on observables—that is, using only quantities that could be experimentally measured,…

Now, this brings up an interesting question: if a sound wave is a vibration of matter, and a photon is a vibration of electric and magnetic fields, what exactly vibrates when matter acts as a wave? The upsetting answer is that there is no directly measurable quantity to correspond to the matter wave itself. This…

We presented de Broglie’s proposal that wave–particle duality works for matter in the same way it does for light. That is, although light usually behaves as an electromagnetic wave, it sometimes acts as a particle (photon). At the same time, while electrons mostly behave as particles in CRTs, they sometimes exhibit wave-like behavior. We also…