Why is *light* classed as both a wave and also as a partcle, the 1st has mass, the 2nd has no mass,?

Answer 1

wave particle duality can only mean one thing. Photons behave as either given the constraints of experiment. I would personally go for wave as a fairer explanation of photn behaviour and that the particle is inferred from our 3 dimensional universe (spatially). Imagine our world was two dimensional, that we lived as infinitely thin slivers on a flat surface. In this world, all three dimensional objects passing through would cause very odd observational behaviour. For instance as a three dimensional practical joke we could push a sphere from above the surface and through it. The 2-D observer would see a point become a broadening line reaching a maximum breadth equal to the diameter of the sphere and then gradually thinning to a point before disappearing. Its mind bending but, pehaps the particle behaviours we appear to observe are only the limits of our dimensional perception. The true(r) description being a multidimensional wave string pervading our reality and behaving as both.
The wave string itself may have no intrinsic mass, but as it transfers energy through interaction with matter particles, mass is implied.
Just a thought

Answer 2

There is no reason that a particle has to have mass - thats just an assumption of yours.

In fact, everything in existence has this dual nature. Remember in both cases we are modelling what reality is like.

Taking light specifically though, wave like behaviour is clear when you look at phenomena like interference, polarisation and the doppler effect. All of these can only be explained by light being a wave.

Particle like behaviour occurs in things like the photoelectric effect, single photon two slit experiments etc.

In fact, light has a dual nature.

Answer 3

According to quantum physics, the particle-wave duality applies to both light and matter. A stream of particles will behave like a wave, and electrons in their "orbits" around atomic nuclei are defined as waves.

Photons have momentum but no mass. As others have pointed out, you can't apply your intuitive understanding of the physical world to quantum physics.

Whether a photon appears as a particle or a wave depends on how you look at it. Photons (or particles) propagating through space are best described as waves. When one interacts with matter, it appears as a discrete packet of energy (or mass) at a particular point, thus the particle model applies. These point interactions are referred to as "collapsing the wave function".

Answer 4

Don't try and visualise quantum mechanical stuff - you are doomed to failure and it will always lead you the wrong way. The toughest part of learning this kind of thing is getting over the urge to visualise, to miss quote the matrix 'Free your mind' !
Mass has nothing to do with wave particle duality. For what it is worth photons have zero rest mass but then have energy so behave as if they do have some tiny mass.

Answer 5

No one knows why light has the properties of both particle and wave, but certain experiments have made us realize that it does.

Look up information on the double-slit experiment to see how light as well as beams of electrons can each be viewed as both particle and wave. The conclusion should involve interference, showing wave-like characteristics, and also particle-like characteristics when you see what you would expect to see. Strangely enough, it all depends on how it is observed!

Answer 6

It all comes down to defining a photon, which is an energy packet. That packet does not have a fixed dimension so it can be compact -behaving like a particle, or it can spread infinitely -behaving like a wave. the photon does have a fixed energy defined by h*nu, so you cant split a photon into little photons. to understand how a photon can be compact like a particle and infinitely spread out like a wave, one must take into account the role time and space play into the measurement of the photon.

Answer 7

The way it behaves can be explained by considering light as particles (photons) or by considering light as a wave. Mass converts directly into energy through e=mc^2. So doesn't matter whether you view it as pure energy or pure mass.

Answer 8

It all depends on how you look at it... and how you measure it... and what you are looking for, the context is important - if you want to find out where a particular photon is in time and space you have to see light in terms of paticles; if you want to see how light moves you have to see it in terms of waves... a particle can tell you WHERE it is but not the DIRECTION in which it is moving...
something like that.

Answer 9

Eric's right. light exists as either or both particle and wave. There have been some experiments with the idea of dark matter that might be able to explain why but as for now NOOOBODY KNOWS!! 8O

Answer 10

sometimes its easier to say that light acts as photons,e.g: waves need something to travel in because a wave is a wobble and for a wobble you need something to do the wobbling, but there's nothing in space to wobble so it has to travel as particles. but sometimes its easier to say that it acts as a wave,e.g: if light waves hit a material they can give electrons energy so the electrons can "jump" out of an atom.