Thread: Minor question

Now I am completely ignorant of science, I can't tell a photon from an electron.

Anyway, I just got one question about that really basic experiment with the photon being in two places at once, How do they know the photon didn't just split into two and go through both slits that way?

Interference. Basically, if you fire a wave through two slits you get an interference pattern. If you fire particles, you don't. When you fire just a single electron at a time through the double slits, you still get an interference pattern, even though you can measure that only one electron came through (destroying the pattern in the process). I'm sure there are other ways to tell, but that's what I can come up with off the top of my head.