Scientists have long known that Albert Einstein skipped something a century ago when he analyzed Brownian motion—the jiggling of particles in a fluid, such as pollen in water. Now, researchers using measurements of unprecedented precision have observed the discrepancy between Einstein’s model and a single particle’s path.
In a landmark 1905 study that helped establish the existence of molecules and atoms, Einstein chalked up Brownian motion to random collisions among particles and a surrounding medium’s molecules.