Build and test a mini wind turbine, pinwheel, or decorative wind spinner. On a plane, a motor-powered propeller spins to push air. On a wind turbine, a rotor spins when pushed by air. How do the number, shape, and position of the propeller or rotor blades affect the rate of spinning? Experiment and find out! 

Materials: 

• Electric fan (or a breezy day outdoors) 
• Cardboard 
• Boxboard (thin cardboard)  
• Scissors 
• Tape 
• Brads (a.k.a. brass fasteners; if not available, can substitute pencil, straw, or toothpick) 
• Toothpicks or wooden barbecue skewers (optional) 
• Markers or colored pencils (optional) 
• Scraps of fabric, trash bags, or other flexible materials (optional) 
• Bendable wire or pipe cleaners (optional) 
• Hot glue (optional; adult supervision recommended)