La spinta di Archimede

In this video, we explain Archimedes' principle, which states that a body immersed in a fluid experiences an upward buoyant force equal to the weight of the fluid it displaces. We begin by considering a fluid in static equilibrium and defining a volume of fluid. We analyze the forces acting on this volume, including the downward gravitational force and the upward pressure forces exerted by the surrounding fluid. The resultant of these pressure forces must balance the weight of the fluid for equilibrium, resulting in a buoyant force equal to the weight of the displaced fluid. When we replace the fluid volume with a solid object of the same shape and size, the resultant pressure forces remain unchanged, as they depend only on the shape and dimensions of the enclosing surface, not the material. However, the weight of the enclosed volume can vary depending on the material, affecting whether the object sinks or floats. If the object's weight is greater than the displaced fluid's weight, it sinks; if less, it floats.