I was wondering about photon's interaction with matter, and why photons dont slow down. They seem to always bounce in a straight line at the same speed (I think), as if some force is charging them forward after the bounce. First, what is this? I've heard of experiments where we actually did slow them down, and they can be absorbed and bounced by matter, so I wanted to know if they interact with matter in such a way that we could spin one, like a curve ball thrown by a pitcher, and make them curve their flight path.
Can someone explain this, in English (back it up by math if you need to but I'm not a physicist, I just like to learn about the fundamental ideas)?