Top Load Washer - Description of Agitator
Many Top Load washers have a "traditional" agitator. The agitator is approximately 17" tall and has spiral fins that turn through the water during the wash cycle. This action moves the water, which in turn moves the clothes down against the agitator into the water and up the sides of the washer.
The following video discusses the importance of selecting the correct water level and shows how the agitator works: