All the vertical axis wind turbine science fair projects kits allow you to build a generator that runs off of a magnetic induction using 4 pre-wound coils and 4 magnets rather than a snap and plug. You can customize the windmill by changing the generator or making your own blades.
Using a simple picture wire you can show how wind power can produce heat. We think of wind as cold. But when the mechanical energy of wind is turned into electricity it easily produces heat.
Divide your class into groups. (After all, scientists work in groups.) Each group change one variable. Ask each group to present their project to the class and see which variable is more productive.
Change size or shape of blades.
Change the material used for the blades.
Which one produces more heat? Which one produces the most electricity?
Which one starts up faster with less effort?
Which produces more energy... a wind turbine or a hybrid (wind/solar)?
Tip: You can use a hair blow dryer to produce the "wind."