why are stones in a river smooth, but rocks near the ocean jagged and irregular?

Question

Water should smooth out eventually the rocks by the sea or am I wrong?

In: 2

Answer 1

Sea is VERY good at eroding rocks in the right conditions. Depends how long the rock has been there and what it is made of. But look at sand, sand is just very very very smooth rock, smoothed down to tiny particles. There’s no smoother rock in a way. Big chunky rocks by the sea have either got there fairly recently, or are made from harder stuff than the shells and sediments sand are made of. Come back in a million years, they’ll be smooth.

Vice versa with rivers, plenty of jagged rocks. Cut myself on one just last year in fact!