The Inertial Balance consists of two rectangular metal platforms supported by a pair of spring steel strips. With one end clamped to the side of a table the other end is free to swing or oscillate back and forth. Adding mass to the free end increases its inertia and causes it to oscillate more slowly. By comparing the periods of the apparatus with known masses to the period of an unknown mass, the value of the unknown mass can be determined.  To determine the inertial mass of an object directly, without relying on gravity to assist in the student's calculations.