Students in grades 3 and 4 enjoyed a unit on variables. To help them learn that in order to test a single characteristic in a design, you can only change one variable. Bugsocopters, fun paper twirling designs, came to the rescue. First the students were given a standard Bugsocopter to experiment with. They had to figure out what made it twirl clockwise and what made it twirl anti-clockwise. Then they were given a series of tests to complete. For each characteristic that they had to test they had to select a design that changed in only one way from the standard Bugsocopter. So for shorter wings, the bugsocopter had to be identical to their standard but only have shorter wings. They tested six different designs: for wings apart, for more paper clips, for short bodies and so on. Students also learned that you have to repeat the test a number of times before you can decide whether the change in design made the bugsocopter fall faster, slower or the same, or twirl faster, slower or the same. The fun part of this unit is being allowed to stand on tables to drop the two Bugsocopters from the same height!