Identical discs are stacked one on top of another to form a freestanding tower. The

bottom disc can be removed by applying a sudden horizontal force such that the rest of the

tower will drop down onto the surface and the tower remains standing. Investigate the phenomenon

and determine the conditions that allow the tower to remain standing. Theoretically，the dynamic

analysis is carried out by stages，and it is found that the key to judge whether the tower collapses

lies in the position of the tower at the moment when it hits the ground. In the experiment，the ro-

tating shaft of the motor is used to drive the rope to pull the disc to exert horizontal

force，which improves the con- trollability and repeatability of the experiment. The effects of the

height of the horizontal force point，the ratio of the disc thickness to the radius and the number

of layers on the stability of the tower are investigated. The theoretical and

experimental trends are in good agreement，and the differences between them are analyzed and

explained.