Rulers	Damping
The rulers are held in a clamp. To show the effect of damping, three rulers can be used as follows. One separate ruler shows the undamped behavior. Two rulers with some viscous fluid like honey in between show the damped behavior. This demonstrates that the natural frequency is not changed by adding damping. The settling time, for instance, can be reduced significantly. The effect of holding the clamp in your hand versus holding it steady on the edge of a desk, shows that energy dissipates when vibrations are damped in the 'fixed world' of a system. N.B.: Do not use water as a damping fluid, because the water will evaporate quickly. If the layer of water becomes too thin, the damping increases dramatically. Then the surfaces are pressed thightly together causing a large friction. Any viscous fluid like honey will maintain a layer that is thick enough.