Today in Technology History

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December 20

One century ago, the inventor of a machine used to generate static electricity was born.

Robert Jemison Van de Graaff was born in Alabama on December 20, 1901. Van de Graaff (pronounced VAN-duh-graff) graduated from the University of Alabama. He then studied physics at some of the world's most prestigious schools: the Sorbonne (where he took classes with Marie Curie), Oxford (as a Rhodes Scholar), Princeton (as a researcher) and M.I.T. (as a professor).

When Van de Graaff studied advanced physics in the 1920s, researchers were facing a new challenge: in order to continue investigating atoms and radiation, scientists needed more powerful streams of high-speed particles.

Using simple equipment -- a silk ribbon, some tin cans, a small motor -- Van de Graaff built a device that could speed up particles and create a very high electrostatic charge. During the 1930s, he refined his "Van de Graaff generator," and built larger models capable of producing millions of volts.

A Van de Graaff generator usually looks like two metal spheres sitting atop two columns. The bigger the spheres, the higher the electrical voltage they can store. One giant version -- capable of producing bolts of "man-made lightning" -- was big enough to hold a laboratory inside each sphere.

Van de Graaff generators were briefly useful for powering X-ray machines, for treating cancer, and for physics research -- but they were soon replaced by more powerful devices. Small models of Van de Graaff generators, which can fit on tables, are still commonly used in physics classes for teaching students about static electricity.

After WWII, Dr. Van de Graaff started a company that sold electrostatic generators. He died in 1967.

Related links:

• Click here for a biography of Van de Graaff.

• Click here to read more about how Van de Graaff generators work.

• This page has several pictures of a giant Van de Graaff generator.

• Use these links to read more about the Van de Graaff generator, and the instruments that preceded and followed it.

 

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