Brownian motion

Brownian motion is when tiny particles, like dust or pollen, move around randomly in liquids or gases. This happens when tiny molecules in the liquid or gas bump into the particles and push them in different directions.

Imagine you are in a pool with lots of other kids. Everyone is splashing around, jumping and moving in different directions. You are one of the particles in the water and the other kids are the molecules. Some kids bump into you and push you in one direction, while others push you in another direction. This is what is happening to the particles in Brownian motion.

This kind of motion was first observed by a scientist named Robert Brown, who was studying pollen under a microscope. He noticed that the pollen particles were moving around in water and thought they were alive. But really, they were just being pushed around by the molecules in the water, which is now called Brownian motion in his honor.

Scientists study Brownian motion because it can tell them about the properties of the liquid or gas the particles are in. They can measure how fast the particles move and how often they change direction, which can tell them how concentrated the liquid or gas is, and what other particles might be in it.

So, Brownian motion is just the random movement of tiny particles in liquids or gases, caused by collisions with the molecules around them.