We're All Waves

Hi, I’m a student here at U of I. Recently, I was having a discussion with someone about frequency and how everything in the universe had a certain frequency. She refused to believe me and demanded proof. I was hoping you could direct me as to what topic to look for, journals to check, or best of all, someone I can contact. I can’t seem to get the link for physics teachers to work.
- Dave Wetherell (age 21)
Urbana, IL, USA

I've left our old answer in below, but wasn't happy with it. Here's a replacement.

I think your friend would agree that everything has an energy. Or at least they should agree that everything has some range of energies, even if it doesn't quite have a single definite energy. Now the point is that in quantum mechanics, energy is just another name for frequency, measured in different units. The conversion factor is just Planck's constant, h. This identity is not just some verbal definition. The entire successful structure of quantum predictions is based on the identification of what we call energy with the frequency of the changes in the phase of the quantum state.

On a historical note, the relation E=hf between frequency and energy was really the first start of quantum mechanics, proposed by Planck in 1900. The connection to wavelengths was first proposed by A. C. Lunn at the University of Chicago in 1921, based on the connection between time and distance required by Special Relativity. DeBroglie came up with the same idea on the same grounds independently in 1923, and was more successful in propagating it. In some ways the history is the opposite of what Adam seemed to suggest.

Mike W.





Our old answer follows.


 I agree with you in that everything has a frequency. To get there, let me backtrack a bit.

First of all, it's easier to talk in terms of wavelength. Frequency and wavelength are related by the velocity. velocity=(wavelength)*(frequency). For photons, that's just the speed of light.

Here's the principle you'll want to learn more about. I'll just give you a taste of it here. In 1923, Louis deBroglie predicted that the wavelength of matter was related to it's momentum.

wavelength = h/p

In that equation, h is Plank's constant and p is the momentum.

This helped explain how a beam of electrons (particles) can interfere in the same way that light does in the famous 2 slit diffraction experiments. It asserted the astonishing fact that particle can behave like waves (and vice versa). The reason we don't notice big objects (like people, pencils, etc) having wavelike properties is that Plank's constant is very small (h = 6.6e-34 Joule seconds), which means the "wavelength" of macroscopic objects is to incredibly small that any effects due to this can't be seen.

If you'd like to learn more about how all matter has frequency and a wavelength, I'd suggest reading more about deBroglie.

Adam

(published on 10/22/2007)