wave-particle duality

  photons, do they have mass or are they massless?  photons do play a big role in the actions within a fusor, so knowing what you can about them is a tool in imagining what happens inside the poissor.

I will have to accept the wave-particle duality for the moment.

 
  this text is pasted from an actual wikipedia article, and it illustrates that a photon is massless, and it is a particle in some respects.  all the hyperlinks are working so clicking on them takes you directly to the wiki site, and it is easy to get lost there.  
 
Photon
 
 
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has no rest mass; this allows for interactions at long distances. Like all elementary particles, photons are currently best explained by quantum mechanics and will exhibit wave–particle duality, exhibiting properties of both waves and particles. For example, a single photon may be refracted by a lens or exhibit wave interference with itself, but also act as a particle giving a definite result when quantitative momentum (quantized angular momentum) is measured.