Botanist — Robert Brown (Montrose, Scotland 1773 – London 1858) was a Scottish botanist, among the most important naturalists of his time. He took part in exploratory expeditions to Australia, where he collected and classified thousands of plant species. In 1827, observing pollen grains suspended in water under the microscope, he noticed that the smallest particles carried out an incessant zig-zag motion, later called Brownian motion. He could not explain its cause, but his observation proved crucial: in 1905 Einstein interpreted it as an effect of collisions with water molecules, providing decisive proof of the existence of atoms. Brown is also credited with identifying and naming the nucleus of the cell.
Trivia
To rule out the idea that the motion was due to the ‘vitality’ of the pollen, Brown repeated the observation with dust from inanimate matter, even fragments of the Sphinx, finding the same ceaseless motion and thereby showing it was a physical, not a biological, phenomenon.
Theories and contributions
- Brownian motion — Incessant, random motion of particles suspended in a fluid, caused by collisions with molecules; the basis of the proof of the existence of atoms.
Appears in chapters
Linked atoms
1 linked atoms.