Buoyancy is a fundamental force in fluid mechanics. When an object is placed in a fluid like water, it experiences an upward force called buoyancy. This force acts opposite to the object's weight, which pulls it downward. The interaction between these forces determines whether an object will float or sink.
Archimedes' principle states that the buoyant force on an object equals the weight of the fluid displaced by the object. This principle explains why ships float and why objects feel lighter in water. The formula shows that buoyancy depends on the fluid density, displaced volume, and gravitational acceleration.
Whether an object floats or sinks depends on the balance between buoyancy and weight. When buoyancy exceeds weight, the object floats. When weight exceeds buoyancy, it sinks. This is determined by comparing the object's density to the fluid's density. Objects less dense than the fluid will float, while denser objects will sink.
Buoyancy has countless real-world applications. Ships float because their overall density is less than water, despite being made of steel. Submarines control their buoyancy by adjusting water in ballast tanks. Icebergs demonstrate that only about ten percent floats above water. Hot air balloons use heated air, which is less dense than cold air, to achieve lift.