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By the end of the lesson, you will be able to:
- understand how the power of water can be used to lift a
weight;
- use linear measurements and simple construction techniques
to build a working waterwheel;
- use ICT to log data, produce graphs and investigate connections
between the size of the wheel, size of pulley, the amount
of water and the rate of flow;
- research current and past uses of water power to provide
a source of energy.
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National Curriculum Links
Science: Sc1 Scientific Enquiry, Sc3 Materials and their Properties,
Sc4 Physical Processes.
Design and Technology: Knowledge, skills and understanding, breadth
of Study.
Geography: Knowledge and understanding of environmental change and
sustainable development.
Part A - Introduction
Water power has been used historically to grind cereals and operate
machinery. In more recent times water turbines have been used to generate
electricity. Currently research is being undertaken to harness the
power of waves and tides as further sources of sustainable energy.
Discuss with children any visits they may have made to watermills.
Talk about their experiences of the power of moving water.
Part B - Materials
Large aluminium pie dish, dowel, cotton reels, wood to build a stand,
small mass, strong glue, string, source of water.
Part C - Construction of waterwheel. Groups
of three or four children
Study the photograph above carefully.
- Carefully cut out the flat centre circle of the aluminium
pie dish.
- Divide the circle into eight equal sections, as shown in
the diagram.
- Cut along each line until 15 mm from the centre.
- Carefully fold each section to make a ledge, as indicated
by the red broken lines.
- Use sections of wood to build a simple stand large enough
to hold the wheel. See photographs. Drill holes in both sides
to take the dowel.
- Push a piece of dowel through the centre of the wheel, place
a cotton reel on either side of the wheel, position it between
the two sides of the stand and glue the cotton reels to the
wheel.
- Glue a cotton reel to one end of the dowel to act as a pulley.
- Attach a small mass to the pulley with a short piece of
string.
- Check that when the wheel is rotated the string winds around
the pulley and raises the mass
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Part D - Using the waterwheel
The simplest way to demonstrate the waterwheel is to place it in
a large bowl and gently pour water from a jug onto the blades of the
wheel. This should provide enough energy to raise the mass. The water
can then be reused (think conservation!) If you have a stream or shallow
river nearby which can be used safely, then the design could be adapted
to operate in those environments.
Part E - Teaching points
There are obvious opportunities to develop children's understanding
of designing and constructing fair tests and considering the factors
that may alter outcomes: size of pulley, size of blades, force and
quantity of water.
Research could be undertaken to discover how waterwheels have been
used throughout history and how the force of water is used in different
ways to generate electricity.
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