brownian motin
Kindly refer to the link given below to know about brownian motion :
https://www.meritnation.com/ask-answer/question/what-is-the-brownian-movement/matter-in-our-surroundings/4782986
https://www.meritnation.com/ask-answer/question/what-is-the-brownian-movement/matter-in-our-surroundings/4782986