, 12 February 2011 (UTC) 
 :You can see how the centrifugal pump works at the dinner table. Take a knife and hold it at one end keeping it flat to the table.  Put the salt pot touching the knife at the same end as your hand then rotate the knife so that it pushes the pot round in a circle.  As you push the pot round its momentum (and the friction with the table in this case) causes it to continue in a straight line rather than move round in a circle with the knife, thus the pot moves outward. 

 :It just the same with the pump, the impeller blades move in a circle because they are fixed to the centre bearing but the water tends to move in a straight line thus water at the centre soon finds itself on the outside of the pump. No mysterious forces are needed, just Newton's first law that bodies continue in straight line motion.    23:18