Setup: A cylinder is suspended from a cylindrical cup with the same volume. The cup and cylinder are hung from a weight scale and measured to weight 13.5 N. The cylinder is then submerged in water. When water is added to the cup, the weight scale should read the same as the original weight of 13.5 N.

Observations:

• When the cylinder is submerged in water the weight scale reads less due to the buoyancy force of the water. According to Archimedes' principle this buoyancy force is equal to the weight of the water displaced by the cylinder. In this example you can see that it was 3.5 N.
  
• The volume of the cylinder and the inside of the cylindrical cup are the same.
• When the cylindrical cup is filled with water the weight scale returns to the weight of the cup and cylinder alone since the volume of water in the cup is the same as the volume of water displaced by the cylinder.