Lesson Y7-U03-L05

Y7-U03-L05 Waterfalls: A Landform of Erosion Quiz: KS3 Geography, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson Y7-U03-L05, Waterfalls: A Landform of Erosion: 20 multiple choice questions for the KS3 Geography (National Curriculum), Unit 3: Year 7: Rivers and the Water Cycle, written with Revision Ninja.

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The 20 questions

  1. Which rock sits on top of a waterfall?

    • Mud carried in suspension by the flowing water
    • Loose gravel that the river has deposited there
    • Soft rock, which wears away quickly and is undercut
    • Hard rock, which wears away slowly

  2. Which rock wears away faster at a waterfall?

    • Both rocks wear away at exactly the same speed
    • Hard rock, because it contains more mineral grains
    • Soft rock, the weaker band lying below the fall
    • Hard rock, the tough cap on top of the fall

  3. What is hydraulic action?

    • Dissolving soft rock with slightly acidic water that slowly eats away at the chalk
    • The force of moving water pushing into and cracking the rock
    • Stones scraping and grinding against the rock as the river carries them along the bed
    • Stones knocking together and becoming rounder as they tumble along the river bed

  4. What is abrasion?

    • The force of moving water pushing into cracks in the rock
    • Water dissolving soft rocks such as chalk and limestone
    • Stones carried by the river scraping and grinding against the rock
    • Mud floating inside the water and making it look brown

  5. What is the deep hole at the base of a waterfall called?

    • A gorge, the steep valley left behind the fall
    • An overhang, the hard rock sticking out above
    • A plunge pool, carved out by the falling water
    • A meander, the bend that the river forms

  6. What is undercutting?

    • Water dissolving the hard cap rock from above until the top layer slowly crumbles away
    • Soft rock being worn away from beneath, leaving hard rock overhanging
    • Stones knocking together until they become round, smooth pebbles on the river bed
    • A river dropping its load on the flat land near the sea, forming a wide delta of sand

  7. What is a waterfall?

    • A steep drop where a river falls down a step in the rock
    • A deposit of sand built up where a river meets the sea
    • A narrow channel carrying water from one river to another
    • A bend in a river where the water flows fastest on the outside

  8. What is an overhang at a waterfall made of?

    • Mud and gravel deposited by the river
    • Sand carried in suspension by the water
    • Hard rock sticking out above the soft rock
    • Soft rock that has been undercut and worn away

  9. A river flows over hard rock lying on soft rock. After many years the soft rock is worn back under the hard rock. What happens next?

    • The hard rock has no support and collapses into the pool
    • The soft rock grows back to support the hard rock
    • The river deposits sand that fills in the gap
    • The river stops flowing over the rock completely

  10. Which order shows how a waterfall forms, starting from the rock before any erosion? (a) overhang collapses (b) soft rock undercut (c) hard rock lies on soft rock (d) waterfall retreats

    • c, a, b, d
    • b, c, a, d
    • c, b, a, d
    • d, b, c, a

  11. Which change would best show that a waterfall has moved backwards over time?

    • A wide delta of sand spreading out into the sea
    • A flat floodplain stretching across the valley
    • A river bend forming a deposit of mud on the inside
    • A steep-sided gorge stretching upstream from the fall

  12. In a waterfall, which rock is most likely to be undercut by the river?

    • The hard rock lying on top of the fall
    • The overhang that is hanging over the drop
    • The soft rock lying below the hard rock
    • The plunge pool sediment at the base

  13. Which erosion processes carve the plunge pool at the base of a waterfall?

    • Solution and suspension, dissolving and floating material
    • Hydraulic action and abrasion, the water's force and scraping stones
    • Traction and deposition, rolling and dropping of the load
    • Attrition and saltation, stones knocking and bouncing along

  14. A pupil says soft rock sits on top of a waterfall. Which correction is right?

    • Hard rock sits on top, and soft rock lies below it
    • Both rock types sit side by side at the top of the fall
    • Soft rock sits on top, but it is undercut by hard rock
    • Soft rock sits on top, and it wears away slowly

  15. A waterfall has moved backwards over thousands of years. What is left behind it?

    • A wide delta of sand where the river meets the sea
    • A lake of still water sitting behind the fall
    • A flat floodplain with many meanders on it
    • A steep-sided gorge that runs back upstream

  16. Why does the hard rock collapse after the soft rock is worn away?

    • It has no support underneath, so it cannot hold its own weight
    • Hard rock dissolves in water after it is undercut
    • The water becomes too cold to hold the rock up
    • The plunge pool fills with sand that pushes it over

  17. Explain why a waterfall could not form where all the rock is the same hardness.

    • The water would flow faster there, so no fall could form
    • A waterfall needs salt water, which only forms over identical rock types
    • Hardness does not matter, because all rock is worn away at the same speed
    • Without rock of different hardness, the river cannot wear one part away faster than another

  18. After the hard cap collapses, the fall moves back upstream. Which best explains why the gorge walls are steep?

    • Rivers always cut sideways in the same way, making flat banks
    • The fall keeps eroding backwards, so the valley walls stay steep
    • Solution dissolves the sides of the valley into a flat slope
    • Deposition builds the walls of the gorge up into steep banks

  19. How could a geographer tell that a waterfall has moved backwards over time?

    • By measuring the rainfall at the top of the waterfall
    • By finding a gorge stretching upstream behind the present fall
    • By checking the colour of the water at the plunge pool
    • By counting the number of tributaries feeding the river

  20. Which statement about hard and soft rock at a waterfall is correct?

    • Hard rock wears away quickly and forms the plunge pool
    • Soft rock sits on top and wears away slowly
    • Hard rock sits on top, and soft rock below wears away faster
    • Hard rock and soft rock wear away at the same speed

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