GREAT SCIENTISTS

The man behind the 'Zeeman effect'.

Pieter Zeeman, born on 25 May 1865, was awarded the 1902 Nobel Prize in Physics together with Hendrik Lorentz. In 1892 Lorentz presented his electron theory, which posited that in matter there are charged particles, electrons, that conduct electric current and whose oscillations give rise to light. Lorentz's electron theory could explain Zeeman's discovery that the spectral lines corresponding to different wavelengths split up into several lines under the influence of a magnetic field, also called the 'Zeeman effect'.

Zeeman worked as a professor as well as Director of the Physics Laboratory at the University of Amsterdam / Universiteit van Amsterdam. In 1923 a new laboratory, specially erected for him, was put at his disposal, a prominent feature being a concrete block weighing a quarter of a million kilograms, erected free from the floor, as a suitable platform for vibration-free experiments. The institute became known as the Zeeman Laboratory of Amsterdam University. Many world-famous scientists visited Zeeman there or worked with him for some time.

Photo: Physicists Albert Einstein and Paul Ehrenfest visiting Pieter Zeeman at his laboratory in Amsterdam, circa 1920s.