Why do ships float while coins sink? Discover the invisible force that keeps objects afloat.
Buoyancy is the upward force exerted by a fluid that opposes the weight of an immersed object. This fundamental principle explains why objects float or sink.
Discovered by the ancient Greek mathematician Archimedes, buoyancy follows a simple rule: The buoyant force equals the weight of the displaced fluid.
"Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object."
Adjust the parameters to see how buoyancy changes
The heated air inside is less dense than the surrounding cooler air, creating buoyant lift.
By adjusting ballast tanks, submarines control their buoyancy to dive or surface.
Hollow structures displace enough water to support weight while staying afloat.
A 1m³ block of wood (ρ = 600 kg/m³) in water (ρ = 1000 kg/m³):
Buoyancy affects everything from icebergs to oil spills. Now that you understand the basics, observe floating objects around you!