Experiments on ductile materials have indicated that cavity formation and coalescence is a major failure mechanism. The present research will consider dynamic cavitation in certain metals and polymers. In the physical situation to be modeled, a stress wave is sent to the center of a solid ball of the material. There is no void initially. After the wave leaves the center, a hole may develop in the material as the result of a singular solution of the underlying equations. This work may lead to a simple predictor of failure initiation in situations where the loads increase slowly and monotonically.