Brownian motion

Brownian motion is the random movement of very small particles in a solution or suspension caused by their collisions with moving molecules of the liquid.

This phenomenon was first studied in detail in 1827 by botanist Robert Brown. He observed through a microscope the random movement of dust particles suspended in water. Brown concluded that this movement was caused by water molecules hitting dust particles.

Later, scientists showed that Brownian motion is a manifestation of the thermal motion of liquid molecules. When they collide with particles, molecules transfer part of their kinetic energy to them, as a result of which the particles acquire chaotic motion.

The intensity of Brownian motion depends on the size and mass of the particles, as well as the temperature and viscosity of the liquid. The smaller the particle size, the more intense their chaotic movement. An increase in liquid temperature also leads to an increase in Brownian motion.

Thus, Brownian motion is an important property of colloidal systems and suspensions, allowing one to estimate the size and mass of particles, as well as the parameters of the liquid medium. It plays a fundamental role in processes such as diffusion and sedimentation.