I have learned of quantum theory and I am doing a 4,000 word essay (IB FTW...). My question is "is light a particle or wave, and what effects it and why." I am going to be doing Thomas Young's double slit experiment which would show that light behaves as a wave (with DeBroglie's Hypothesis). I am having problems though because I need to do an experiment that shows that light is a particle also. I know that people have thought for centuries that light is particles because it bounces off things, though I don't know if that would be valid enough for an essay. Plus I think I would score higher if I did an experiment (instead of making "assumptions" in the essay). Edit: Wow, i'm retarded... I forgot about the photoelectric effect experiment. Do you know of any other experiments that are cheap enough for a high school student to do?