Answer: The answer is that both rocks and boats float because they displace a certain amount of water. With rocks, the weight of the rock is greater than the weight of the volume of water it displaces, so the rock sinks.
Boats, on the other hand, are designed to displace just enough water so that their weight equals the combined weight of themselves and all their contents. This means that when a boat is floating in water, it will be balanced between two forces: gravity pulling down (and trying to sink it), and buoyancy pushing up (and keeping it afloat).
Last modified: October 29, 2022