Components: A. Base, B. Bracket, C. Adapter, D. Track, E. Ball,F. Photogate, give the signal of timing end, G. Built-in touch sensor-give the signal of timing end, H. Magnetic Absorber—with built-in magnet, used to absorb the falling ball, I. Cable port for touch sensor built-in the base.

To measure the buoyancy acted on the sinking object.