PhySP18SS5.4.27 Mean old Robert Brown. Biologist whose mistake changed the world in 1820. He looked through a microscope and thought that the pollen grains were alive because they were randomly moving around. Turns out they figured out later that the pollen grains were not alive (no vis viva). They were simply being bounced around by the water molecules that surrounded them. Turns out the water molecules are ALWAYS moving and bouncing into each other in this chaotic manner. We call it, you guessed it . . . Brownian Motion.