Today, students present their catapults to the class. In their presentations, they explain what their original idea is and how that idea and design changed throughout the construction process. They then have three tries to make it in the center target.
STEP FIVE: CHANGING VARIABLES
Students now are going to change a variable on their catapult. For example, they may change the material that they wrap around the marble. They may first wrap the marble in tape, and test the accuracy of the launch multiple times. Then, they may wrap the marble in string, and again test the accuracy of their launch. Then, they will wrap nothing around the marble, and test the accuracy of the launch. They must test three variables. Some variables that are commonly tested are 1. how far the launcher is pulled back, how many rubber bands are used, the location of the placement of your catapult, the base of the catapult, the length of the launcher, and the material of the launcher. After presentations, students spend today testing three variables of their choice. Students record this data in a data chart in their packet.