text: you have a rubber ball 2 inches in diameter and 100 milliters of water how much does the ball displace?   diameter = 2 in radius = 1 in = 0.0254 m  volume sphere (4/3)*pi*radius^3 = 6.9 m^3 = 69ml  oops! yeah the ball would have to more dense than the water and be completely submerged for the above answer to be correct.