World Met. Day 2005

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.

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

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.