There's a very commonly held view that atoms can never touch: bring them together slowly, and you reach a point where they begin to repel. But in this video Professor Philip Moriarty explains that really isn't the case.
Philip is a little irritated by many of the discussion online about how molecules repel, never to touch each other. So allow him to talk atoms, van der Waals forces, and internet stupidity. He's both amusingly indignant and factually interesting at the same time. I'd love to have been taught by this guy. [Sixty Symbols]