Look at the weather with the naked eye

Brownian motion is invisible to the naked eye.

As for the movement of dust and pepper in boiling water, it is caused by the irregular flow of air and water, which is different from Brownian motion principle.

Brownian motion is due to the irregular motion of molecules, which leads to the irregular motion of smaller particles (such as pollen). The particles of dust and pepper are too large, and the molecules act evenly on them.