Thursday, September 11th, 2014
2:00pm - 3:00pm, in McCormack 1-207

Ethan Bolker

UMass Boston

The Spinor Spanner, or Houdini's Neutron

Abstract: Take a wrench (or any similar thing you have handy) and attach it by three (or more) cords to fixed points (doorknobs and such) in the room. If you rotate the wrench 360 degrees about some axis the cords are tangled. If you rotate it 720 degrees they're not. This magic trick isn't magic at all - it reveals a remarkable and remarkably little known property of the space we live in. The spinor spanner has deep connections to quantum mechanics which this talk is not about. It is about explaining just why the trick works - starting with gluing up Mobius strips and ending with some moderately sophisticated topology, presented without technical vocabulary or prerequisites.