Energy transfer by waves: two primary modes = (electromagnetic waves, compression/transverse waves propagating through a medium)
1) electromagnetic waves:
Using a particle model for the wave (photons for light), energy transfer is similar to that by discrete moving object -- particles carry the energy from one place to another in the absence of a medium.
Energy delivery: discrete moving object uses inertia and momentum to transfer the energy from itself to the target. Photons are massless, so the energy delivery mechanism must be different.
2) compression/transverse waves propagating through a medium:
Energy passes through the medium with little to no net flow of the medium itself. In transverse water waves, when the energy wave passes by, to first order, the water particles move in vertical circular paths. This is different from energy transfer by a moving object in that the moving object must displace itself to the target position in order to deliver the energy -- resulting in a net flow of object material.
