The Moment of Inertia Disc is an invaluable tool for studying rotational energy. With a powerful magnet it can be afixed to a wall or table for experimentation. The bearing provides the disc with an incredibly smooth, unimpeded rotational movement. Through experiments with this device it is possible to determine and study the torque needed for acceleration on a rotational axis. The unit comes with 6 metal pins with string holes as well as holes drilled throughout the disc to shift mass from one place to another and observe the degree to which rotational energy is affected by thhe distribution of an objects mass. Consider using with Eisco Labs Table Clamp Pulley (PH0297A) for setting up a hanging weight experiment in which the student can observe the moment of inertia and record data accordingly.