Brownian motion is a phenomenon in which particles suspended in a fluid (such as air, water, or gas) exhibit random, erratic movements. This motion is caused by collisions with the molecules of the fluid, and was first observed by the Scottish botanist Robert Brown in 1827 when he observed the random movement of pollen grains in water. Brownian motion has since been studied and described mathematically as a stochastic process, where the particle's position changes over time in a random and unpredictable manner. This research area is important in various fields such as physics, chemistry, biology, and economics, as it provides insight into the behavior of small particles and molecules in a fluid environment. Researchers continue to study Brownian motion to further understand its underlying principles, develop mathematical models to describe its behavior, and explore its applications in various scientific disciplines.