Formation of a waterfall

Question 1

Part one - differential erosion

Answer 1

Where waterfalls (found in the upper course of the river) flows over bedrock with varying levels of resistance, the softer rock erodes first (this is known as differential erosion)
This creates a step in the river where the rock meets

Question 2

Part two - erosion

Answer 2

Over time: the erosional processes of hydraulic action, corrasion and solution erode the less resistant rock

The river falls further and so increased hydraulic action at the base forms a plunger pool

Question 3

Hydraulic action

Answer 3

sheer force of water breaks apart the rocks, and the air bubbles get into the rock and crack it

Question 4

Corrasion

Answer 4

rock scrapes and wears away the river bed

Question 5

Solution

Answer 5

minerals and segments are dissolved in the water flow

Question 6

Part three - collapse of waterfall

Answer 6

The rocks fall into the plunge pool and continue to widen and deepen it through corrosion and attrition (rocks in the plunge pool hit off of each other, eroding the plunge pool further)

The hard rock becomes unsupported as it has been undercut by the softer rock, and collapses due to the lack of support. The waterfall then retreats upstream