The unit consists of two transparent glass tubes, attached to a frame, each having two valves at the bottom. With the help of two valve mode, the object can be removed from the measuring tube without considerable loss of liquid. Two o-rings and a scale at center is provided to measure distance and is used for measuring sink time for a specific section. Spheres of different materials and volumes are used to examine sink speeds of objects in liquids. Two tubes separately can be filled with different density fluids for comparison.