Understanding Waterfalls

What is a common visual characteristic of a waterfall?

• Water disappearing underground

• Water flowing in a straight line

• Sheets of water cascading over a cliff edge

• Water flowing uphill

Where are waterfalls most commonly formed in a river's course?

• Middle course

• At the river's mouth

• Lower course

• Upper course

What type of rock layer is most resistant to weathering and erosion?

• Uppermost rock layer

• Hard rock layer

• Middle rock layer

• Soft rock layer

Which process involves water droplets trapping air and breaking rock?

• Attrition

• Abrasion

• Hydraulic action

• Sedimentation

What forms at the base of a waterfall due to erosion?

• A plunge pool

• A cave

• A sand dune

• A river delta

What happens when the softer rock layer is eroded under a waterfall?

• The waterfall disappears

• The waterfall becomes taller

• A cave forms

• The river changes direction

What causes the overhanging harder rock to collapse?

• Volcanic activity

• The weight of the rock and river

• Earthquakes

• Wind erosion

What geological feature is evident in the Icelandic waterfall example?

• A single rock layer

• Alternating hard and soft layers

• A flat rock surface

• A sandy riverbed

What is a visible sign of erosion in the Niagara Falls example?

• A sandy beach

• A dry riverbed

• Protruding harder rock layers

• A smooth rock surface

What natural phenomenon can be seen at waterfalls due to sunlight?

• A sandstorm

• A snowstorm

• A rainbow

• A tornado