Hobbies And Interests
Things You'll Need
Instructions
Throwing Arm and Axis
Place two pencils on top of each other so that they overlap 2 inches. Hold the pencils firmly in place. Wrap electrical tape around the entire overlap.
Center a pencil across the throwing arm 3-1/2 inches from the front. This pencil is the axis. Attach the axis to the throwing arm by tying two rubber bands around it in a crisscross fashion.
Place the four penny rolls together so that looking down, you have a cloverleaf shape. Wrap electrical tape around the entire length of the rolls. This is the trebuchet's counterweight.
Place the counterweight along the front of the throwing arm. Attach it to the throwing arm by wrapping electrical tape around the counterweight and throwing arm.
Unfold the paper clip so you have a straight wire. Coil the wire around the back of the throwing arm. 1/4 inch of the wire needs to extend past the arm. This is the aiming pin. Fasten the coil to the throwing arm by wrapping electrical tape around it.
Upright Supports
Place two pencils next to each other, making sure the eraser ends are on the same side. Slide a rubber band 1 inch onto one of the pencils from the unsharpened end. Wrap it three times around both pencils. Spread the pencils apart so the eraser ends are 3-1/2 inches apart. Slide the rubber band between the pencils. Wrap it twice between the pencils. Slip the rubber band over one of the pencil's ends.
Attach a pencil to the spread-apart eraser ends by wrapping rubber bands around the pencil and eraser ends in a crisscross fashion. This is one of your trebuchet's upright supports.
Make a second upright support. The overlaps at the supports' tops are the cradle for the trebuchet's axle.
The Frame
Place three pencils together so they overlap 2 inches on the ends. Secure them to each other by wrapping the overlapping sections with electrical tape. This is the frame's central beam. The entire frame will consist of three beams.
Center the upright supports 3 1/2 inches apart on the center beam. Attach them to the beam by wrapping rubber bands around them in a crisscross fashion.
Stand the supports up. You will need to keep them in place with a pencil for each support acting as a prop. Fasten each prop to an end of the the central beam and the point right below the upright support's cradle with rubber bands.
Place a pencil under the upright supports' front corners. This is the frame's front beam. Attach the front beam to the upright support with rubber bands. Use another pencil for the rear beam. Tie it to the supports' rear corners with rubber bands.
Runway and Sling
Cut two strips of poster board: 3-1/2 inches by 12 inches and 1 inch by 2 inches. The first strip of poster board is the runway. The second strip is the sling's pouch.
Place the runway on the trebuchet's frame so that it protrudes 1 inch from the front. Tape it to the frame with electrical tape.
Fold the sling in half so that the 1-inch sides touch. Punch a hole close to the center of the 1-inch edges with the scissors.
Cut a 12-inch length string and a 13-inch length of nylon thread. Heat the ends with a lighter until they melt into a clear plastic bead. This will keep them from fraying.
Thread the 12-inch nylon string through one of the pouch's holes. Thread the 13-inch nylon string through the pouch's other hole. Fasten the strings to the pouch with knots.
Tie the 12-inch string's free end to the throwing arm's rear, 3/4 inches in front of the aiming pin. Keep it in place by wrapping electric tape around it. Place the throwing arm's axis in the trebuchet's cradle.