Final answer:
The Bod Pod, which is not explicitly referenced but is a method of estimating body composition based on air displacement, measures the volume of air displaced by a person to calculate body fat percentage.
Step-by-step explanation:
The method of estimating body composition based on air displacement of a body is known as the Bod Pod or air displacement plethysmography.
This is different from the hydrostatic weighing described in the provided reference materials, which uses water displacement to estimate body composition.
The Bod Pod measures the amount of air displaced by the person's body when seated inside the chamber, and since the density of fat and muscle tissue is different, this allows for the calculation of the percentage of body fat and lean body mass. This technique is considered accurate and is commonly used for assessing body composition.