2B40.u6 - Volume Displacement
To show how two spheres of identical mass, but different densities will determine the volume of water displaced by each.
Fill a 2L beaker with water from the tap and place a camera on the beaker. Make sure there are two rolling object bases to place each of the masses onto to prevent rolling.
With the camera up and the beaker full of water, place the small mass in the beaker and show that it sinks to the bottom and note how much volume of water was displaced. Then remove the small mass and place the larger mass in the beaker. Observe that the ball floats, but the same amount of volume of water was displaced.