Phi Top

Product Code: SE-7594


The PhiTOP is an egg-shaped top (a prolate ellipsoid) that can be spun by hand to stand up on end. This is a fascinating demonstration used by Nikoli Tesla in 1893.

When spun with a magnetic stirrer, the PhiTOP replicates Tesla’s famous Egg of Columbus demonstration. An alternating magnetic field will spin the PhiTOP from rest along its minor axis due to Lenz’s law of electromagnetic induction. As the angular speed increases, the center of mass will rise, and the PhiTOP will spin along its major axis.


  • PhiTOP
  • Mirror Stand