Floating is a fragile bargain. The water seems to take over as a body settles on its back, yet that ease depends on a negotiation between the upward force of buoyancy and the downward pull of weight. A breath, a lifted head or a shift in the hips can change the terms.Stillness is not magic. Under Archimedes' principle, water pushes upward with a force equal to the weight of the water displaced. Wh...More