43. Van de Graaff Machine


In 1929, a National Research Council Fellow at Princeton’s Palmer Physics Laboratory named Dr. Robert J. Van de Graaff began to develop an electrostatic generator that could produce high energy protons for investigations into the nuclear structure.  This Rhodes scholar moved on to MIT in 1931 where he completed the device, which he called a Van de Graaff generator.  In this picture, Dr. Van de Graaff demonstrates an early model of his instrument by turning a crank to produce static electricity.  The largest Van de Graaff generator, built in 1933, measured forty feet tall, with aluminum spheres fifteen feet in diameter, and was capable of producing 7 million volts of electricity.  In addition to their value as tools of nuclear physics research, Van de Graaff generators proved useful for many other scientific, industrial, and medical purposes, including cancer therapy.  Today, these devices are found in many museums, where regular demonstrations teach public and school audiences about lightning and electricity.