Wringing
Great stuff.  We need more of these types of science tidbits on HN.  And good links by the commenters too.<p>I love Feynman&#x27;s classic style of &quot;explaining to a 5 year old&quot; on Cold Welding.<p><i>The reason for this unexpected behavior is that when the atoms in contact are all of the same kind, there is no way for the atoms to “know” that they are in different pieces of copper. When there are other atoms, in the oxides and greases and more complicated thin surface layers of contaminants in between, the atoms “know” when they are not on the same part.<p>— Richard Feynman, The Feynman Lectures, 12–2 Friction</i>