Year 7 Topic 2 Waterfalls Flashcards
1
Q
In which stage of a river do waterfalls normally form?
A
Waterfalls normally form in the upper stages of the river
2
Q
Where do waterfalls form?
A
Waterfalls form where a hard overlies a softer rock
3
Q
How do waterfalls form?
A
Falling water and hard rock erode the softer rock below creating a plunge pool.
4
Q
How does the waterfall overhang form?
A
The soft rock is undercut by erosion processes such as hydraulic action and abrasion. The debris swirls around the plunge pool deepening and enlarging the pool to create an overhang.
5
Q
What usually happens after a waterfall overhang forms?
A
The overhang collapses as the weight of the rock is no longer supported.
