Purpose:Indicate how electrons really flow through a conductor.
Description:Nails are driven into one side of an inclined plane in an orderly pattern, representing the lattice of a crystal, and into the other side in a random fashion, representing the polycrystalline structure of a metal. Ping pong balls represent free electrons traveling through the material. In spite of the much larger number of nails on the structured side, the balls move more quickly than through the random array of fewer nails. The slope of the inclined plane models the potential difference, and the interaction of the balls with the nails models the interaction of the free electrons with the ion lattice of the material.