How is moving water or wind able to erode a surface more quickly than still water or air?

Answer 1

The erosive power of wind, like the erosive power of running water, is dependent on its ability to abrade by the movement of one material against another material. Because of the density and mass of water as compared to air, it would be logical to assume that moving water can move and abrade more material than moving air. Rainwater has the added ability to act as an acid on many rock forming minerals, thus enhancing its erosive powers. Additionally, freeze/thaw cycles can expand joints in larger rocks, breaking them into smaller rock units and making the entire mass more vulnerable to acid attack. And finally, water feeds plant growth, the roots of which can penetrate rock crevices, expand, and aid erosion.

Answer 2

Because wind slowly and constantly wears the object down, but it takes a long time. Water, however, not only does this in the rivers and streams, but falls in the form of rain, further wearing down the object. And if this wasn't enough, it freezes in the little crevaces and expands as Ice. When it melts, not only does it disappear leaving a huge gap, but then the object collapses into further smaller pieces which is then relentlessly worn down by the same process.

Answer 3

1) Friction.

2) Destructive impacts on the surface caused by energy transfer from dust and debris carried along in the fluids.

3) Water dissolving elements in or at the surface; this happens with still water too, but if the water is moving, the solution is less concentrated and therefore more able to dissolve the solute.

Answer 4

I venture that it is because water has two physical states liquid and as a solid - ice. Water has also a higher density than air.

Answer 5

the impact of the water hitting the surface erodes it away

Answer 6

This is just a guess but water erosion is more constant than wind erosion and faster moving than erosion by ice.