Paraboloid focus demo instrument

The invention discloses a paraboloid focus demo instrument which comprises an outer cover, a base, a bottom plate, a paraboloid block and a pinball, wherein the base is fixedly connected with the upper surface of the bottom plate; the paraboloid block is detachably arranged at the upper part of the base; a ball outlet is formed in the center of the paraboloid block; the outer cover covers outsidethe base and the paraboloid block; a paraboloid block replacing port for removing the paraboloid block in a horizontal side sliding manner is formed in a side wall of the outer cover; and a ball taking hole directly opposite to a through hole in the side wall of the base is further formed in the side wall of the outer cover. According to the paraboloid focus demo instrument, the pinball naturallyfalls from a pitching hole, falls down to a paraboloid along a trajectory parallel to the central axis of the paraboloid, and then moves obliquely upward through the rebound of the paraboloid until the pinball collides with a