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Al Tobias (wat4y) - Office: Gibson S123 & Physics 218, (434) 924-0538

Physics Demo Manual

Demonstrations are cataloged according to PIRA Bibliography


Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.

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 Electric Fields And Potential
 Current and Resistance
 Electromotive Force And Current
 DC Circuits
 Magnetic Materials
 1x 2x 4x Coils and Bar Magnet
  video  - Hanging Ring and Magnet
 Flash Bulb Coil
  video  - LED Coil
  video  - Eddy Current Pendulum
  video  - Lenz's Law and Eddy Currents
  video  - Eddy Current Tube
  video  - Jumping Ring
 Eddy Current Levitation
 Eddy Current Levitation 2
 Eddy Currents 2
  video  - Transformers
 Electric Motor
 Hand Crank Generator
 Bicycle generator
 Complex Circuits
 Semiconductors And Tubes
 Transmission Lines and Antennas

 video  - Transformers


To demonstrate the basic operation of a transformer and some related phenomena.


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  DEMO VIDEO DOWNLOAD / no audio / 1920x1080 / 24.19Mb/s / 782MB size  

  DEMO VIDEO DOWNLOAD / no audio / 854x480 / 5.69Mb/s / 184MB size  

This set-up can be used in many different ways, the most dramatic being "Jacob's Ladder". Using the 250 turn winding as a primary and the 23,000 turn as a secondary, a voltage of about 10kV is produced. When the copper wires are placed at the output of the secondary and the juice turned on, an arc will form between the wires and climb upwards until the distance between the wires is too great whereupon the arc will dissipate and another will immediately form at the bottom again, repeating the process.

The double light socket can be plugged into a secondary and lit, ie. 250 turn to 500 turn step up, or 500 turn to 250 turn step down. Different primaries and secondaries can be used with a VARIAC to measure different voltages and currents.

We also have a winding assembly with 5 sets of windings to be used as a set down transformer with a 500 turn primary. The nail points touching will weld together due to much increased current.


  • Connecting Wires
  • Jacob's Ladder
  • Leybold transformer apparatus
  • Light Socket
  • Variac