Erosion – The wearing away and removal of material by turning material into a solution or by attrition, abrasion or hydraulic action
Types of erosion:
Solution: The sides of the river dissolve into the water.
Attrition: Wearing down the river bed by bouncing into the sides of the river and breaking off particles.
Abrasion: Wearing down the river bed by grinding, rubbing, scratching and scuffing like sandpaper.
Hydraulic Action: River flow compresses pockets of air against the banks of the river into cracks, which expand and fracture the rock over time.
To remember that erosion is attrition, abrasion, hydraulic action and turning material into a solution, learn the following story:
Eros, he rose up upon (erosion) a hydrant and started acting on it (hydraulic action). First, he tried being a donkey and made a braying (abrasion) sound that gave everyone a headache, so the solution (solution) was two headache pills. They did stay, however, to see Eros do a trick on (attrition) the hydrant.