Energy and Windmills

Students create windmills and make predictions on how many
 marbles can be lifted according to the number of
windmill blades.

Before students began they wrote their hypothesis and drew out a scientific diagram.
Then student's started with one blade and recorded how many marbles could be lifted. (0)  Next, the added a second blade and repeated the experiment.  In the end students were able to lift 10 or more marbles with six blades.