What is a whirlpool?

• The word "whirlpool" refers to any body of water that contains rotating currents. The currents form a vortex, or cavity; the cavity tends to suck anything around it into the center of the whirlpool.
  
  

Forces and whirlpools

• Whirlpools are caused by two forces acting against each other. Water spinning creates a force going in one direction, while the water pressure of the surrounding water creates a force going in the opposite direction. According to Moment of Science, the interaction of these two forces creates a condition in which the water continuously spins and is continuously pulled to the center. Flushing a toilet creates a temporary whirlpool of this nature.
  
  

What happens when you flush the toilet?

• When you flush the toilet, a chain pulls on the flush valve, causing the bowl to quickly fill with water from the tank. At the same time, the discharge hole opens at the bottom of the toilet, causing water to go out. The pressure from the water going into the bowl and out of the bowl at the same time creates the whirlpool effect.
  
  

Purpose of whirlpool effect

• Without the whirlpool effect, waste material would not go down the drain of the toilet. The whirlpool sucks everything in the toilet towards its center. Thus, waste products eliminated into the toilet are pulled towards the center and down the drain.
  
  

Clogs

• A toilet clogs when something blocks the discharge hole from remaining open long enough to create the whirlpool effect. When a clog occurs, water and waste material are not sucked down the drain of the toilet. Instead of going down the discharge hole, the water continues to fill the bowl, and the toilet may overflow.