Jean-Baptiste Perrin
Name in native script: Jean-Baptiste Perrin
1870–1942, Lille, France, New York City, United States
French physicist who established the reality of atoms through quantitative studies of Brownian motion and estimated Avogadro's number; he received the 1926 Nobel Prize in Physics.
Perrin was born in Lille, studied at the École normale supérieure in Paris, and taught at the Sorbonne. In the early twentieth century he measured the Brownian motion of suspended colloidal particles and showed that the results agreed with molecular-kinetic predictions, providing strong experimental evidence for the existence of atoms and molecules.
Using independent measurements, he determined Avogadro's number by several methods, presented in his book Les Atomes (1913). He received the 1926 Nobel Prize in Physics for work on the discontinuous structure of matter, especially his investigations of sedimentation equilibrium in suspensions.
Nobel-winning work
Perrin won the 1926 Nobel Prize in Physics 'for his work on the discontinuous structure of matter, and especially for his discovery of sedimentation equilibrium'. From 1908 he measured Brownian motion and the height distribution of suspended particles, confirming Einstein's 1905 theory and extracting Avogadro's number Nₐ ≈ 6–7×10²³. His results gave atoms decisive experimental reality.
Workplaces: Sorbonne, Paris, University of Lyon
France