The double slit experiment w/ Professor Brian Cox

Transcript

There is one experiment which encapsulates all the properties of the quantum world. It's called the double slit experiment. Let's say you have an electron gun that emits particles and then you have a barrier that has two slits cut in it and a screen. The electrons can go through one slit or the other one depending on how they come out with maybe a bit of a spread because they rattle around a bit when they go through. But that's not what you see.

You see sort of stripes. a stripe on the screen where you get lots of electrons and then a stripe where you get very few or none and then another stripe where you get lots and then a stripe where you get very few or none. That pattern is exactly the same pattern that you would get if you sent waves through the slits. And waves have the property that they can interfere with each other. The fact that you get it from particles is interesting.

But here's another interesting thing. You still get that pattern if you send one particle at a time through the slits.