posted on Jul, 28 2013 @ 12:55 PM
A very simple experiment that throws up a lot of interesting questions regarding the nature of light, and specifically its constituent...the
Photons fired from a flashgun introduce energy upon a drum set cymbal to elicit a tone. At face value, it would suggest that photons have mass, but
this mass has never been detected. So, how is a pulse of light managing to set a large enough vibration in a cymbal so that it perturbs the air around
the cymbal for our ears to detect as a low tone?
If the photon has no mass, then congruently it has no nucleus, and thus, we cannot treat it as a 'solid' object colliding with another 'solid'
object. The photon is the force carrier of electromagnetism, and what it lacks in mass, makes up for in momentum, yet without mass, how is a photon
able to cause perturbation? The answer must lay in the way it is absorbed and emitted by the electron within the atom, and how that quantum action
rigidly follows the law on the conservation of energy?
For the sake of illustration (and argument) I'll use the classical Rutherford-Bohr model of the hydrogen atom. A simplistic construct defining the
atom as having a central positively-charged nucleus - the proton, and a single orbiting negatively-charged electron. Both particles have mass, with
the proton being 2000 times heavier than the electron. While the proton is held in place by the strong nuclear force, the electron is held in its
relationship to the proton by electrostatic force.
If an atom is at rest phase, its lowest energy level, and its electron absorbs a photon, an increase in the atom's energy value occurs, causing the
electron to jump to a higher energy orbit. The atom cannot hold onto this increase of energy, so the electron emits a photon which allows the electron
and the atom to return to rest phase. It is this jump from lower energy orbit to higher energy orbit back to lower energy orbit that supplies the
energy causing the cymbal to resonate and perturb the air around it. Obviously, a single photon being absorbed by a single atom is not enough to cause
a large enough resonance in the cymbal to perturb the air. It's down to the transfer of kinetic energy initially supplied by the momentum of the
photons fired from the flashgun.
As well as being the fundamental building blocks of solids, atoms are essentially relay stations for pumping energy around, where every energy
interaction breaks down the wave/particle duality into the everyday reality.