Play Catapult

Rip the erasers into small chunks and pull the end cap off the back of a pen. Slide the ink tube out of the main pen tube.

Measure 2 inches down a Popsicle stick and cut the stick at this length with the scissors. Repeat. Measure and cut two Popsicle sticks at 1 3/4 inches in length. Set aside the leftover stick sections.

Glue the sticks together in the shape of a rectangle. Glue the remaining sections of the 1 3/4 inch sticks flat against the two 2 inch-long pieces at the bottom corners of the rectangle. These pieces are going to be the arm supports.

Cut a notch in the middle of the top end of each support arm measuring 1/3-inch deep and 1/10-inch wide with the scissors.

Measure 2 inches down another Popsicle stick and cut it at this point. Glue the ends of this piece in the notches.

Carve a small hole in the center of this stick with the tip of the scissors. Insert half of a rubber band through the hole. This half of the rubber band will now have a loop shape. Pull the other half of the rubber band down through the center of the loop.

Cut the pen ink tube 1 2/3 inches from the end and cut the spoon handle in half horizontally. Discard the half that is not attached to the spoon.

Tape the spoon handle to the center of the pen ink tube and insert the spoon through the looped side of the rubber band.

Push the thumbtacks into the stick that sits between the support arms until the points of the tacks go into the end of the pen ink tube. Set three eraser chunks onto the spoon and pull the spoon back to fire the ammunition.

Lash together three 8-foot spars for the front triangle (or front face). Use square lashings to connect the bottom spar to the two upper spars and diagonal lashing to connect the apex of the triangle.

Begin with the square lashing. Start with a clove hitch on the spar that will be closest to the ground, leaving 12 inches of the free end. Then, lash it in front of and over the top of the second spar, then behind the upright spar and down in front of the second spar. Finally, take it behind the upright spar immediately above the clove hitch. Continue for at least three more turns around each spar. Frap the lashing by drawing the running end two times around the lashing turns, that is, between the spars. Finish off with another clove hitch on the upright spar.

Start the diagonal lashing with a timber hitch. Follow the timber hitch round for three turns and then reverse and make three turns around the other fork. Secure the lashing by adding a clove hitch.

Lash two 12-foot back brace spars to the front face of the catapult. Two of the spars should be fastened to the front face about two-thirds of the way up. Use square lashings to connect these two spars to the front face.

Fasten another two 12-foot spars at the bottom of the front face using square lashing. These four spars are then lashed together at the apex of the triangle using a diagonal lashing.

Attach the pivot bar to the bottom of the throwing arm about 2 feet up from the end of the throwing arm. Use square lashing to connect these two spars.

Attach the pivot bar to the front face on top of the two back brace spars that are attached about two-thirds up the front face. Lightly lash the pivot bar to the front face -- do not connect it so that it cannot move, you need to leave it room to move. Use the hammer and nail to attach the tin can to the end of the throwing arm.

Nail the pulleys to the bottom spar of the front face, one on each side. Connect the middle of the launching rope to the end of the throwing arm using a clove hitch.

Run the two ends of the launching rope through the pulleys and lay them back beside the two back brace spars. Your catapult is now operational.

Cut the end of one of the 6-inch pieces of wood in order to make a 45 degree angle; you will need to cut both ends. Cut the top right corner and the bottom left corner of the piece of wood.

Screw a 6-inch piece of wood that hasn't been cut to the 12-inch piece so that they form a 90-degree angle. The 6-inch piece of wood should stand vertical when the 12-inch piece is horizontal. The 12-inch piece will form the base, so it should be able to lie flat when the 6-inch piece is attached.

Glue the 6-inch piece of wood between the two pieces you have just attached. The piece should form a triangular join between the longer 12-inch piece and the 6-inch piece which is standing vertically. Repeat steps 1-3 so that you have two identical structures, of a long 12-inch piece lying horizontally and flat, with a 6-inch piece vertically attached. Between the two, a diagonal 6-inch piece gives support.

Attach the two sections of the frame together using the four 6-inch pieces of wood. Attach each end of the 12-inch pieces of wood together by screwing a 6 inch piece of wood between them. You will now have a rectangular frame. Screw a 6-inch piece of wood between the top of the 6-inch piece wood which stands tall of the frame. Finally, attach the 45-degree joins together by screwing a 6-inch piece of wood between both.

Drill a hole in the remaining 12-inch piece of wood, roughly 2 inches from one of the ends. The hole should be around 1/8 inch wide and pass horizontally through the wood. Attach the eyehook 3 inches from the end of the 12-inch piece of wood, at the opposite end to the hole you have just drilled. Use the tack to attach a styrofoam cup immediately above the eyehook. Drill a hole near the base in each of the vertical 6 inch pieces of wood.

Feed the metal bar through the holes you have drilled. The 12 inch piece of wood with the Styrofoam cup on it is the "launcher," and should be placed between the 6 inch vertical pieces. The metal bar will run through the vertical 6-inch pieces and the launcher to form a pivot point. Place putty on both ends of the metal bar to hold it in place.

Place an eye hook on the front of the frame, in the center. Place rubber bands between the two eye hooks. The more you attach, the stronger and more powerful the catapult will be. Place an object in the cup, pull the bar back and release to use your catapult.

Create a base using three layers of one-prong-wide LEGO strips on a flat 8-inch by 8-inch LEGO base plate. Set the base walls parallel to each other with four rows of prongs between them, each row an equal distance in from the edges of the plate.

Construct two A-frames using two 2-inch-long single-prong LEGO struts with holes connected with an arm pin at the top and another 2-inch strut at the base to make a triangle. Connect another 2-inch strut at each base corner of the triangle and secure with pins to make the "A" shape. Mount the A-frames to the three-layer walls created in the previous step with pins.

Attach two single-prong LEGO struts with holes to each end of a two-prong by 16-prong plate to create the catapult arm. Secure with an additional two-prong by 16-prong plate underneath to sandwich the struts.

Attach a lead fishing weight to one end of the LEGO catapult arm by threading copper wire through the outermost strut holes. On the opposite end of the arm, thread a 3-inch piece of elastic string through the strut holes and tie a key ring to the loose end of the string.

Cut a small strip of T-shirt, approximately 3 inches long and 1 inch wide. Stitch one end together so the T-shirt becomes a cup-like pouch to hold the projectile. Wrap the sewn end around the key ring and stitch in place.

Slide the end of the catapult arm closest to the fishing weight onto a LEGO axle through the strut holes closest to the long plate. Insert the axle through the pinnacle of the A-frames to complete assembly of the catapult.

Pull the T-shirt scrap away from the catapult, stretching the elastic line and raising the lead weight. Load the T-shirt with a marshmallow, pull back tightly and release to launch the marshmallow up to 30 feet.