Tin-Boat Challenge

 This is probably my favorite challenge  all year long.  Watching these 4th graders learn about buoyancy and then try to duplicate it with a piece of aluminum foil is fun to watch.  The goal of this challenge is for the students to design a boat with a square foot of aluminum foil and six straws.  No tape or connecting products at all can be used.  Then the boat must float 250 pennies.  
Students add pennies to their boats slowly to see if they can make the goal.  All student show growth in their designs, and most complete the goal, some reached over 400 pennies!  A sketch drawing is made first, then they start the building, testing, recreating process know as the Scientific Method.  It is very satisfying to watch these kids learn all about their designs and improve on their thoughts.