Wind machine discovery

As one student investigates the wind machines, he discovers an interesting phenomenon. Even though he turns the solar cell upside down to stop the sun from shining on the cell, the fan blades keep turning. He puzzles over the situation and postulates that the sun must be bouncing off the ground and hitting the solar cell from underneath. He then involves other students in a discussion about what is occurring. Finally, the two girls discuss alternatives to the use of solar cells and how they can be replaced by batteries.


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