The Brownian motion is named after a British Botanist Robert Brown who first observed it. It is also known as Brownian movement.
Brownian Motion can be defined as:
The random motion of particles suspended in a fluid resulting from their collision with the fast-moving molecules in the fluid.
In simple words, it’s just a random motion shown by small particles suspended in a fluid (liquid or gas) as shown below:
As evident from the above-shown figure, a particle collides with other particles and thus changes its path. This interaction between particles leads to their random motion which is also commonly known as zig-zag motion. Brownian motion is a transport phenomenon which is, it transfers or exchanges mass, momentum or energy between the particles.
We know that the unbalanced interactions between the particles cause the Brownian motion. Now let us try to understand the factors that affect this motion.
The Brownian motion describes randomness and chaos. This is one of the simplest models of randomness. Hence have many applications in real-world as most of the things on the miniature level are random and have some entropy associated with them. Thus the study of Brownian motion is critical in understanding the real world phenomenon.
Albert Einstein in 1905 gave his theory of Brownian motion after concluding another theory for the same. looking at the idea that the temperature of any substance is directly proportional to its average kinetic energy which these molecules move, it is obvious that this motion is imparted to a larger substance which could be seen under a microscope.
Einstein concluded a diffusion equation from his observation where the diffusion coefficient is similar to the mean squared displacement of the Brownian’s particle. This leads him to determine the size of atoms and the number of atoms present in a particle.