To make a submarine from a water bottle, make holes on one side of the water bottle and tape heavy coins on either end. Attach a flexible straw at the mouth, and add plastic tubing to operate the submarine. Use clay to attach the straw to the bottle's mouth.Continue Reading
Use a screw driver or nail to make three holes, in a straight line, on one side of the bottle. Ensure that the holes are big enough to let water in and out of the bottle.
Tape five heavy coins on either end of the bottle, on the same side as the holes. The purpose of the coins is to weigh down the submarine.
Attach a flexible straw at the mouth of the bottle. Use modeling clay to secure the straw in place, making sure that the area is water tight. The holes and the tip of the straw should face opposite sides of the bottle.
Add a length of plastic tubing at the end of the flexible straw. The length of the tubing will be determined by the depth you want to achieve.
Ease the submarine, holes side down, into a water tank, and allow it to sink. Blow into the plastic tubing to let water out of the bottle, and float the submarine.