well i think there was an experiment done a long time ago where they shot a beam of light onto some gold foil and found that electrons from the foil were knocked out...i'm not too sure on this since it was a while since i've learned this...
anyways, i'm not sure if you're saying that light is made up of particles because it bounces off objects or if you're saying that it could be made up of particles because it bounces off objects...remember, sound waves bounce off objects, but they're only waves...