How Waterfalls Change Over Time

Lesson 5 – page 6

To learn that waterfalls change over time.

To learn that waterfalls retreat backwards.

To learn that when a waterfall retreats a gorge is formed.

To learn that Sipi falls brings benefits as a tourist attraction.

Key Skill = Communication

Lesson Aims

Hard Rock

Soft Rock

Lip

Plunge Pool

Processes

Undercutting

Abrasion

Hydraulic Action

The hard rock forms a lip.

The waterfall retreats backwards leaving a gorge.

Hard rock overlies soft rock.

Erosion of the plunge pool causes undercutting.

The soft rock is eroded to form a deep plunge pool.

The undercut lip collapses into the plunge pool.

Soft rock beneath the hard rock is more easily eroded.

Activity – Draw and annotate the sketches

1 4 6 7

2 5

3

What benefits do Sipi Falls bring to local people?

Case studySipi Falls, Uganda

Explain the employment terms:

Formal SectorInformal Sector.

Extension Activity