Initial experiments can show how the motion of the windmill blades can create electricity, using a fan or hair dryer to simulate the wind. The experiments can prove that electricity is generated by hooking the windmill to a bicycle generator connected to a voltmeter, seeing how much electricity is needed to light up an LED light or a bulb and plotting results on a graph, for example. With larger windmills, create enough electricity to move a teeter-totter or power a radio.
Experiment with different numbers of blades and blades of different length to determine the most effective combination for producing electricity. Use a fan to provide a constant wind speed through a cardboard wind tunnel onto the windmill, to ensure all the combinations are under the exact same conditions. Plot the results on a graph. Use different angles of blade pitch on the windmill – how the blades of the windmill are angled toward the wind – to judge how much electricity is generated. By plotting the results you’ll be able to determine which is the most efficient angle of blade pitch.
When no wind blows, windmill blades can’t turn. Conduct experiments to determine just how much wind velocity is needed to generate power by using a fan and a wind meter, measuring the amount of electricity going to the generator with a voltmeter. This can help show the optimum conditions for the operation of a windmill, and also whether there’s a point at which increased wind speed no longer results in more electricity being generated.
Building a working wind turbine to create electricity that can be stored in generators and used to run appliances makes an ambitious experiment for older students and one that can be conducted as a conclusion to a wind power project. It offers the students a chance to put what they’ve learned into practical use and incorporates other fields, such as math and engineering, as well as working with electricity. The students will need to co-operate in larger groups, although they will need strong teacher supervision.