For example, if you have really large pond and a small pond, and you swim down 3 meters in each of them, the pressure will be the same. Why? (Is it possible to describe this using kinetic theory or molecular motion?). It doesn't really make sense to me; if there's more water, and water pressure spreads equally in all directions, then technically shouldn't the volume/mass of water be factored in as well? i.e. in the larger pond, there would be more water crushing you/exerting pressure on you?