Why is agitation necessary to get clean clothes

People use a variety of methods to

wash clothes. Usually after adding the soap, they‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation

necessary to get clean clothes? 

Answer: The soap micelles formed by soap entrap dirt and grease particles and lie on the surface of the clothes. When the clothes are agitated, these micelles get detached from the surface of the

clothes and go into water.