How to Make a Submarine With Straws & Pennies

Hammer a nail into an empty 20-ounce soda bottle to make three holes in its side. Make the first hole 1/2 inch from the bottom of the bottle, the second should be at the top, about 1/2 inch below where the bottle begins to taper, and the third exactly between the first two. Make the holes in a straight line running from the bottom to the top.

Make a stack of four pennies, a stack of eight pennies and a stack of 12 pennies. Wrap the stacks with aluminum foil.

Place three heavy-duty rubber bands around the bottle so each band circumscribes the bottle just below each hole in the bottle.

Place the stack of four pennies under the rubber band at the top of the bottle, the stack of eight pennies underneath the middle rubber band and the stack of 12 underneath the bottom rubber band. The stacks should sit just beneath each hole in the bottle, but not cover them, and they should stand up from the body of the submarine like smokestacks.

Drill a hole into the lid of the soda bottle. Make the hole slightly smaller than the diameter of your drinking straw.

Push the shorter end of the flexible straw -- the end you would sip from -- through the hole in the bottle cap. Apply duct tape around the seam created between the straw and the bottle cap to make a seal, then screw on the cap and put your submarine in the water. Bend the straw in the opposite direction of the stacks of pennies before you submerge your submarine.