Buoyancy is the upward force exerted by a fluid (liquid or gas) on an object immersed in it. This force opposes the weight of the object, which acts downwards. According to Archimedes’ principle, the buoyant force is equal to the weight of the fluid displaced by the object. It is caused by the pressure difference between the bottom and top surfaces of the object due to the weight of the fluid column above them. Pressure is force per unit area. While buoyancy arises from pressure differences, buoyancy itself is defined as a force. Forces have direction, and the buoyant force always acts upwards.