Expt: Calculating the Buoyant Force

Aim: To calculate the buoyant force exerted by a liquid




  1. Take a liquid of a known density in a beaker.
  2. Select a solid object and attach it to a spring balance.
  3. Note the weight of solid. Record this as the weight of solid in air.
  4. With solid still attached to the spring balance, gently lower the spring balance to immerse the solid into the liquid in the vessel until the solid is completely submerged or starts floating.
  5. Note the weight reading on the spring balance, while the solid is still immersed. This weight will be less than the weight of the solid in air and is known as apparent weight.
  6. Calculate the buoyant force by subtracting the weight in liquid from the weight in air of the solid.
  7. Repeat the same procedure for liquids of different densities and record the observations.


The buoyant force exerted by a liquid is directly proportional to its density. The denser the liquid, higher is the buoyant force it exerts and vice versa.