Challenge: Design a mini wind turbine using recycled materials.     

Bonus points for efficiency and aesthetics! 

Students will work in groups of approximately 5 to incorporate recycled materials as far as possible. This might include plastic bottles, cardboard tubes, CDs, straws, and other common household items. The wind turbine should be functional, able to generate a measurable amount of energy. Consider factors such as blade design, rotor size, and the efficiency of the energy conversion mechanism.