7B20.33 - ESR - Electron Spin

Place the ball without the stem into the apparatus and turn on the magnetic field.  Do not spin the ball.  Switching the direction of the magnetic field also flips the ball 180 degrees.
Precession due to applied magnetic field can also be shown if the ball is spun carefully about a central axis.
Code Number:
7B20.33
Demo Title:
ESR - Electron Spin
Condition:
Excellent
Principle:
Plus and minus 1/2 spin.
Area of Study:
Modern Physics
Equipment:
Teach Spin Apparatus, Standard ball with stem, Special ball without stem.
Procedure:

Place the ball without the stem into the apparatus and turn on the magnetic field.  Do not spin the ball.  Switching the direction of the magnetic field also flips the ball 180 degrees.  Precession due to applied magnetic field can also be shown if the ball is spun carefully about a central axis.  

References:
  • Harold A. Daw, M. Ramona Daw Pomeroy, "The Free Rotator Apparatus", AJP, Vol. 69, # 3, March 2001, p. 289.
  • Malcolm Correll, "Mechanical Analog of Electron or Nuclear Spin Resonance", AJP, Vol. 33, # 4, April 1965, p. 24.
  • Harold A. Daw, "Two Air-Supported Devices for Physics Laboratories and for Physics Demonstrations", AJP, Vol. 33, # 4, April 1965, p. 322.
  • Mark Wilson, "Scanning Tunneling Microscope Measures the Spin-Excitation Spectrum of Atomic-Scale Magnets",  Physics Today, Vol. 59, # 7, July 2006, p. 13.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.