A clear hall or room more than 20 meters long is needed for the balloon competition. The water rocket is best illustrated outdoors. The straws may be cut to 10 cm lengths. The rocket accelerates in the opposite direction as a reaction.
Pressure has nothing to do with the motion of the rocket.
Students will fly a water rocket under various conditions to see the effect of propellant and exhaust speed. Students will write a summary statement of the 3 variables that are important for the flight of a rocket motor. Students will construct a balloon rocket and race them along a guide wire. Tell the class that this is a rocket and you are going to 'fly' it. Release the end which you have pinched off and the balloon will snake off, slithering in random directions.