But what are they supposed to be doing, 
            you may ask? 
            They are learning to store elastic potential energy and gravitational 
            potential energy. 
            Their mission is to construct a "missle launcher" that will 
            make a marble roll across the floor. 
            The materials they can use to do this are: tape, ruler, balloon, popsicle 
            stick, and a foam cup.
            
          
 
          
          
          
          
          
          
          
          
          
          
          
          