Intuition suggests that a flat rock will hit the water with greater force than a spherical one, and experiments uphold that. But a flat rock, interestingly, doesn’t produce the greatest impact force. Instead, it’s a slightly curved rock that experiences peak impact forces. Researchers found this happens because of the thin layer of air that coats the front of the impacting object. For flat faces, this layer is relatively thick and provides a cushioning effect that reduces the peak force and spreads out the impact. In contrast, a slightly curved convex surface traps a thinner air layer, and that lack of cushioning maximizes the impact force. (Image credit: J. Wixom; research credit: J. Belden et al.; via APS Physics)
Curved Rocks Hit Harder
