Buoyancy & Fluid Pressure

A fixed-volume block in a fluid. Buoyant force F_b = ρ_fluid·V_displaced·g. It floats when its density is below the fluid's. Gauge pressure grows with depth: P = ρ_fluid·g·h.

Weight (down)0 N

Buoyant force (up)0 N

Submerged fraction0 %

Floats

Depth h (for P)2.0 m

Gauge pressure P0 Pa

object density 600

fluid density 1000

pressure depth h 2.0 m

Block volume fixed at V = 0.0010 m³ (a 10 cm cube). Densities in kg/m³. g = 9.8 m/s².

Try: raise object density above the fluid density — the block sinks and the buoyant force stops equalling the weight (the extra weight is what the floor must support). Iron (~7900) in water always sinks; ice (~920) always floats.