The Boat/Rock Brainteaser ft Simone Giertz part 2/3

The water will be higher, given that the rock does not float. The rock is initially displacing it's weight in water, but when it sinks it will only displace it's own volume in water (and the ground will do the lifting of the weight). If we assume that the rock is denser than water, then the volume of water needed to displace the weight of the rock is greater than the volume of the rock & when the rock is resting on the bottom the water doesnt have to displace its weight => the water levels will rise.