1. Working with Wind Energy 24 September 2010 Moshe Kam 24 - 25 SEP 20101

2. Activity Goal Build a wind turbine with simple materials The wind turbine must withstand the wind generated by a fan or hair dryer and rotate for up to 1 minute to lift a small object 24 - 25 SEP 20102

3. Activity Objectives Learn about wind energy conversion Design a wind turbine Construct the wind turbine Test the wind turbine Evaluate Performance 24 - 25 SEP 20103

4. Why is this experiment useful to teachers and students? Learn about wind energy and wind turbines Learn about the concepts of forces and motion Learn about engineering design Learn how engineering can help solve societal challenges Learn about teamwork and problem solving 24 - 25 SEP 20104

5. Principles & Standards for School Mathematics Geometry: – Use visualization, spatial reasoning, and geometric modeling to solve problems – Analyze characteristics and properties of two- and three- dimensional geometric shapes and develop mathematical arguments about geometric relationships Problem Solving: – Recognize and apply geometric ideas in areas outside of the mathematics classroom – Apply and adapt a variety of appropriate strategies Communication: – Communicate mathematical thinking coherently and clearly to peers, teachers, and others 24 - 25 SEP 20105

6. What is Wind? Wind is a form of Solar Energy The sun heats the Earth’s surface at varying rates The air above the warmer areas heats up, becomes less dense and rises Cooler air from adjacent higher-pressure areas moves to the lower-pressure areas That movement = wind 24 - 25 SEP 20106

7. Where in the World is Wind? 24 - 25 SEP 20107

8. What is Wind Energy? The process by which the wind is used to generate mechanical energy or electricity Wind turbines convert the kinetic energy in the wind into mechanical and electrical energy 24 - 25 SEP 20108

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10. A Wind Turbine The wind hits the blades… Shaft leads to a gearbox whose output leads to a generator to make electricity Usually has 2 or 3 blades 24 - 25 SEP 201010 WIND

11. The Turbine Blade Operates much like an airplane wing Low-pressure air forms on the downwind side of the blade The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn 24 - 25 SEP 201011

12. Many blade designs 24 - 25 SEP 201012

13. Your Challenge Design, construct and test your own wind turbine design Wind up weight 15 cm as quickly as possible Maximum 1 minute No human interaction! Blowdryer at least 30cm away from turbine 24 - 25 SEP 2010 > 1ft, 30cm 13

14. Turbine Requirements Must have a rotor shaft around which to wind up given weight Must be freestanding (no human interaction) Must use only materials provided 24 - 25 SEP 201014 > 1ft, 30cm

15. Test Procedure Blowdryer at least 30 cm away from turbine No human interaction with turbine Attach weight around rotor Up to 1 minute to wind up weight Record time to wind up weight 24 - 25 SEP 201015 > 1ft, 30cm

16. Materials wooden sticks, spoons bendable wire string paperclips rubber bands toothpicks aluminum foil, plastic wrap tape, glue wooden dowels paper, cardboard 24 - 25 SEP 201016

17. Procedure Teams of 2 Develop and sketch your design Construct initial design Preliminary test Modify design, if necessary Final test 24 - 25 SEP 201017

18. Evaluate Your Design Efficiency of design may depend on – Cost of materials – Speed (rotations per minute) – Power (time to wind weight) Possible measure of efficiency: – Eff. = (Cost of materals) / (time [sec] to wind weight) Are two designs that have the same rotational speed equally as “good”? 24 - 25 SEP 201018