air is forced into the cracks in the rocks, by
water filling them. the crack is made bigger by
that air being forced through and breaks the
rock or land form in half
abrasion
the repeated force of the water hitting the rock
or hitting the rock against the river bed cause
the rock to break up
solution
the chemicals in the water over time dissolve
material off the rock and transports it some
where else
attrition
when the water repeatedly forces rocks into
each other causing them to break up into
smaller pieces