Question: Why do rocks skim the water when thrown correctly?

Sam Geen answered on 24 Jun 2013:

Water has a force called surface tension, where the surface of the water holds together rather than letting the water split into individual molecules. When the stone hits the surface, if it hits it at a shallow enough angle it bounces off the surface as this surface tension keeps it together enough. If you throw the rock at the wrong angle it breaks the surface tension and falls into the water.