1. Bend some coathanger wire to make the crankshaft. The part for the piston has to stick out more than the part for the valve, and the part for the valve has to stick straight up when the part for the piston is lying flat. The flywheel goes on one end and the valve goes on the other end, with the part for the piston between the sticks on the frame. A grownup can help make the right angles.
2. Cut out a big circle of cardboard about the size of a dinner plate for the flywheel and make a hole in the middle to fit the crankshaft.
3. Now it's time to glue the crankshaft on the flywheel. The crankshaft has to stick straight up when the flywheel is lying flat.
4. Cut three short pieces of medium-size straw and poke a hole through for the crankshaft.
5. Two of these straws will go on the wood frame for bearings. If you get the right size straws they will just fit over the craft sticks.
6. The other one is for the piston. Put the straws on the crankshaft like this.
7. Then put the two bearings on the wood frame like this.
8. Now connect the piston. Make the straw for the piston longer or shorter to fit so the shaft turns easily without pulling on the balloon at the top or hitting the bottle at the bottom.