Buoyancy: Archimedes’ Principle

Theory

Every submerged body receives a buoyant force equal to the weight of displaced fluid: $F_b={\rho }_{fluid}{V}_{sub}g$. It floats if ${\rho }_{body}<{\rho }_{fluid}$, and the submerged fraction is $V_{sub}/V={\rho }_{body}/{\rho }_{fluid}$.

What to observe

• Cork (240 kg/m³) mostly above water; wood (600) more than half under; ice (917) ~92% submerged; iron sinks.

Try this

• Change the liquid to mercury: even iron floats!
• Move the pressure sensor deeper.

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