Things You'll Need
Instructions
Blow up and deflate a balloon two or three times to stretch it.
Bend the accordion-like part of a bendable drinking straw as far as it will go, forming an "L" shape with it.
Poke the tip of the long end of the straw into the mouthpiece of a balloon. Tape the balloon to the straw. Seal the opening of the balloon with the tape so no air will be able to escape.
Position the bend so it rests on the rear of the car's roof with the long section of the straw pointing directly in front of the car and the short section pointing upward. Tape the straw securely to the roof of the car.
Blow through the short section of the straw to inflate the balloon. Hold your finger over the end of the straw to prevent air from escaping as you place the car on a flat surface. Remove your finger from the straw and shout, "Gentlemen, start your engines!" as the car speeds away.