" Brownian motion is the random motion of particles suspended in a fluid (liquid or gas) as they collide with the surrounding molecules. This phenomenon is named after the British scientist Robert Brown, who observed it in 1827 while studying pollen grains suspended in water. Here are the key points about Brownian motion: Brownian motion refers to the erratic, random movement of small particles when they are suspended in a fluid medium. The particles move in a zigzag or erratic path, changing direction due to the continuous bombardment of molecules in the fluid.