The real story
Rocks crack off mountains when water seeps into cracks, freezes and expands, a process called frost wedging. Once a fragment reaches a river, every knock against other stones grinds off its corners. The farther it travels, the rounder and smaller it gets. Geologists can tell how far a pebble has come just from how round it is.
The bits it loses become sand that settles on the sea floor, gets buried, and over millions of years can be pressed into new rock and pushed up into new mountains. That's the rock cycle. The world record for skipping a stone is 88 skips.
