Jean Baptiste Perrin

He was an atheist and a supporter of socialism.

Jean Baptiste Perrin had a son named Francis Perrin (born in 1901), who grew up to become a physicist.

He died on 17 April 1942 at New York at the age of 71. His mortal remains were transported to France after the World War II, and buried at the Panthéon in Paris.

Jean Baptiste Perrin was born on 30 September 1870 at Lille in France. His father was an army officer who died due to injuries following the Franco-Prussian War. He had two sisters.

He completed his school education from local schools and graduated from the LycéeJanson-de-Sailly in Paris. Following this he served a year of mandatory military service.

Between 1894 and 1897, he worked as an assistant in Physics and conducted studies regarding cathode rays and X- rays. He received his PhD in 1897.

He was initially appointed as a lecturer in Physical Chemistry at Sorbonne, University of Paris. In 1910, he became a professor there and remained in the post until the German invasion of France during the Second World War.

He conducted research on a variety of topics but his initial studies were related to cathode rays and their nature, which he found to be negatively charged particles. The result of this study was shared by him in 1895.

In 1905, after Albert Einstein published his explanation for ‘Brownian Motion’ in terms of atoms, Jean Baptiste Perrin conducted research to verify the same and was subsequently proved right in 1908. His experiments put an end to the several disputes regarding physical reality of molecules and settled the atomic theory.

His previous research with regard to the particle theory enabled him to calculate ‘Avogadro’s number (N)’, which is the number of gram-molecule of a gas. His experiments consequently led to the establishment of theory of ‘discontinuity of matter’.

His other research work included the effect of X-rays on gas conductivity, disintegration of radium, understanding fluorescence, and the release and dissemination of sound.

Jean Baptiste Perrin is remembered for his research and studies in colloids and his contribution in confirming the Brownian movement. His other significant contributions to science include studies on the nature of cathode rays and validation of the atomic nature of matter.