Why do rocks sink and supertankers float?
For example, a carrier ship launched into the sea will sink until the weight of the water it displaces is equal to the weight of the carrier. It will sink deeper and deeper, displacing more water as it is loaded with more stuff. It is possible to load a ship down until it simply sinks. And it is also possible to shape a rock to float. This usually involves removing enough material to where it is “hollowed out” because this removes enough weight to where the amount of water pushed away as it enters the water is less than the weight of the rock.
