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Anderson Video - Electric Fields on the Atomic Scale

Professor Anderson
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 Forces that are holding the atoms together and what we said is, that it is the electromagnetic force, right. Here's the proton here is the electron, there's some force there which is the electromagnetic force. Yes. Okay. Okay, so his question is, is there a force between him and the other objects in the room that are made up of atoms. Okay, and that's a really good question, right. Let's think about that for a second. When I write this, write a proton and electron, okay. This isn't quite to scale, right? Proton, electron are a little bit smaller, a little bit closer together. So really a proton and electron look like this. Here's the proton, here's the electron right next to it. Okay, if I think about the electric field out here at some point, right there. What does the electric field do to those two charges? Probably small, probably nearly zero. Why is it zero? Because the plus has an electric field that goes like that, but the minus, which is sitting nearly in the same place, has an electric field that looks like that. So everywhere they're equal and opposite and so they almost cancel out. Okay, and so you don't feel a force between you and the table, or you and something else, but you do if you get close enough. Okay. When I go like this, what happened? What happened Sam? When I just did that what happened? Okay, but what do you see right here? Can you see that in front of you? Yeah, what is that? Okay, it's ink that was on me, right, and some oil from my hand that I left on the glass. And if you look really closely here you can see my fingerprint, right? Maybe the resolution on the camera is not good enough but zoom in on your laptop, maybe you can see my fingerprint right there. No, you can't. Okay. What happened was, the stuff on my hand got close enough to the glass that it started to distinguish between the positives and the negatives, and it did feel a force. And in fact it felt so much of a force that it left my hand and stuck to the glass. Okay, that's exactly what happened.