Einstein's Little Machine

Albert Einstein was the ultimate theorist, having spun out mathematical explanations of space and time, gravity, atoms, and quantum phenomena. And yet Einstein also had his experimentalist side too. He grew up in a household where gadgets were all around (his father owned an electrical instrument factory), and he worked in a patent office where a parade of detailed engineering drawings came past his view every day. In fact he built several practical devices and took out numerous patents of his own.

One of Einstein's creations, which he called his "Maschinchen," or little machine, sought to measure voltages at the level of 0.0005 volts. This sort of precision is easy to achieve nowadays but was not possible in 1907, when Einstein developed a contraption which took charge induced on a metal plate by a weak nearby potential and then stored it in a special accumulator; the effect of the small voltage signal could then be multiplied.

Three known versions of this machine are known to exist, at least one of which was used in an experiment conducted by Walter Gerlach (who later worked on the Stern-Gerlach discovery of electron spin). Now, two scientists at the University of Ghent in Belgium have performed computer simulations to show in detail how the Maschinchen worked. Danny Segers (danny.segers@ugent.be) says that he and Jos Uyttenhove are building a replica to better explore Einstein's handiwork.

Segers and Uyttenhove, American Journal of Physics, August 2006
Contact Danny Segers, University of Ghent
danny.segers@ugent.be