Science at key stage 3 (Year 8)
Unit 8G: Rocks and weathering
Section 5: a. What happens to weathered pieces of rock?
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Objectives |
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- that rock fragments become sediment grains which can be transported by water currents and deposited when the energy is dissipated
- to make predictions about where sediment is deposited
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Activities |
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Outcomes |
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Children: |
- Review work on weathering and fragmentation of rocks. Find out pupils' ideas about how rock fragments are transported and changed by asking them to sequence a set of statements/drawings and to explain their sequence. Help pupils to investigate water flow in a channel and its overflow by using square guttering that channels water into a large trough. Use a dye,
eg ink, to track what happens to the current along the gutter and in the trough. Discuss the spreading out of the dye and ask pupils to describe and record where water is moving quickly, and where it is moving slowly, and to use the results to predict where large and small fragments will be deposited.
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- state that rock fragments can be transported by flowing water
- use the results of their investigation to predict where different sizes of sediment might be moved or deposited in a river flowing into a lake or sea
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Points to note |
- Pupils' understanding of how different grains behave can be reinforced by adding a cupful of mixed-sized grains of sediment to a jar of water and swirling it around. Ask pupils to observe which grains roll, which bounce and which 'fly',
eg in suspension.
Safety
- take care that floors do not become wet and slippery
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This unit is divided into sections. Each section contains a sequence of
activities with related objectives and outcomes. You can view this unit by
moving through the sections or print/download the whole unit.
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