What principle is hydrostatic weighing based on?

Hydrostatic weighing is based on Archimedes' Principle, which states that an object submerged in a fluid experiences a buoyant force equal to the weight of the fluid it displaces. This principle is fundamental in understanding how the body’s density can be measured accurately through hydrostatic weighing.

When a person is submerged in water, the volume of water displaced by their body can be used to determine body density by comparing the weight of the person in air to their weight while submerged. The difference in weight provides critical information because it is directly related to body composition. This method is particularly effective for assessing body fat percentage, as it takes advantage of the body's buoyancy and the principle of displacement to derive meaningful measurements.

The other principles, while important in their own right, do not specifically pertain to the mechanisms of buoyancy and fluid displacement involved in hydrostatic weighing.