Jean Baptiste Perrin's 1926 Nobel Prize for Proving Brownian Motion
French physicist Jean Baptiste Perrin won the 1926 Nobel Prize for experimentally verifying Brownian motion and proving that matter is composed of discrete atoms rather than being continuous.
Newsnibs Staff
- 2026-10-01
- Updated 3:05 PM UTC
Jean Baptiste Perrin advocated the atomic theory and proposed a Solar System model for the atom. He also ran a set of experiments meant to settle a debate that had gone on for centuries: whether matter is made of discrete units or is continuous.
The challenge came after Albert Einstein published a paper in 1905 that formulated Brownian motion in terms of atoms. Einstein initially believed that experimental verification was impossible. Perrin accepted the task of verifying the theory experimentally anyway.
Perrin and members of his lab spent months cutting tiny pieces of resin, each about a micrometre in diameter, and suspending them in various solutions. They examined the suspensions with a recently invented ultramicroscope, which uses light scattering to make small objects visible as points of light.
Perrin attached a camera lucida to the microscope, projecting the sample's image onto paper. The researchers sketched the motion of the particles there. They then refocused the microscope to different heights and repeated the sketches, producing a series of cross-sectional diagrams. Together, the diagrams were used to map the complete motion of particles throughout the solution.
Perrin was awarded the Nobel Prize in 1926 for this work.
Photo by Logan Gutierrez on Unsplash
