Are photons waves or particles?

Answer 1

Photons are particles, by definition. Light, however, can be either a particle or a wave. It depends on your expectation when you make an observation. That's right. If you expect to see particles, then light will appear as photons, or particles. If you expect to see light as a wave, then it will appear as a wave.

The Universe let's you, the observer, decide what you see.

One of the most interesting experiments physicists have performed in underestanding the inner workings of the Universe is this: place a photon emitter in front of a two-slit panel (note that if we shine a beam of light at the two-slit panel, we will see a interference pattern), but now we don't shine a beam of light, instead, we shoot out one photon (particle) at a time. So what do we see?

We expect that the photon will shoot out and depending on which direction it is moving, it will either impact the panel, or go through one of the 2 slits. So if we place a photon detector behind each slit, we will detect each and every photon that goes through a slit. And indeed this is what we see.

Now we remove the photon detectors and place a photo-sensitive screen behind the 2-slit panel, and let it sit there for awhile with the photon emitter running. So what do we see after several hours? We see the interference pattern as if a beam of light has been shine through the two slits.

This implies that when a photon could be passing through either of the two slits, it will actually pass through both, and so an interference pattern will result. But if the particle is detected at one of the two slits, then it can no longer be passing through both - it must exist at one or the other, and so no interference pattern appears. So our photon (a particle) still acts as a wave and can effectively exists at more than one location until it is detected at a particular location.

I hope you got this very important point. The photon or any particle for that matter exists in more than one location (actually it exists everywhere and act like a wave) until it is found or observed somewhere.

Answer 2

A photon is a particle, that has a wave function.

Let me explain:

If you excite an atom by heating it up, the electrons will jump to a higher plane of orbit and are said to be "energized". As the atom cools, the electron will fall down into a lower orbit and emit a photon. This is how your basic light bulb works.

When that photon is emitted from the lightbulb, quantum theory tells us that it has a probability wave that expands over time. That is because it's not a "real" particle yet. It only has the probability of existing across a wavefront that propogates through space until it interacts with another particle. Once the photon interacts with another particle and is measured in some way, the probability that it is anywhere other than where it was measured become Zero. At that point, the wave function is said to have "collapsed" and the photon will forevermore behave like a particle.

The topic you are really looking for is: quantum interference, which has to do with observing how quantum particles behave when in their wave-form.

For more information see the classic "two-slit" experiments where light is shown through a two slit in a piece of cardboard and it is proven that a photon, while classicly considered an infinitesimally small energy packet, manages to go through both slits _at the same time_!

Have fun with this, it's good stuff. If you really like and understand it, consider taking the next step and read up on quantum entanglement.

Answer 3

Photons are particles. But light was considered both wave and particles. A double slit experiment conducted by young using light as source produced a fringe pattern. This caused a confusion and a question is light a wave or particles. Scientist concluded that light is both particle and wave. But recently when the same double slit experiment conducted using photons instead of light produced the same pattern. Now the conclusion is it is probability that the photons may end up at random and produce the fringe. Now one can conclude that both fringe patterns are not produced by the same mechanism. So photons are still particles.

Answer 4

Short Answer: Photons are particles.

Less-Short Answer: Photons are particles that behave in wave-like ways.

More Correct Answer: Photons are particles that behave in wave-like ways. The "wavey" nature of photons is governed by the Schrodinger equation, which is a wave equation. The thing that "waves" is the probability of what the particles will do.

Long, Hand-Wavey Answer: Deep down, photons are particles. However, if you get a whole bunch of them acting together, they collectively behave as a big wave. In such a case, most people just neglect the whole particle thing and use Maxwell's equations. They work plenty well, and they're way easier than making sense out of the Schrodinger equation.

Answer 5

A photon, by definition, is a particle. However, it is a particle that has no mass, and it behaves like both a wave and a particle. In physics, it is usually referred to as a particle, but it sure doesn't behave like one in all circumstances.

Answer 6

A photon by definition is the particle refering to light.

Answer 7

It depends on how you look at it - literally. One experiment will show that light has the properties of a wave, another will show it has the properties of a particle. So, depending on circumstances, photons are both.

Answer 8

According to the quantum mechanic, all of particles such as electron, photon,proton,etc. are both wave and particle.
So sometimes, we have to take them as particles to explain something about them, and sometimes as waves.

Answer 9

Light is an electromagnetic wave--an oscillation of the electromagnetic field. However oscillations of the electromagnetic field are quantized: the energy comes in discrete and fundamental chunks. A photon is just such a fundamental chunk of energy belonging to a wave of a definite frequency.

Answer 10

They exhibit properties of both.