Bottle rocket experiments demonstrate several theories of physics -- motion, force, gravity and friction. Your bottle rocket design helps dictate how far and fast your bottle rocket flies, however so does the quality of your bottle rocket's fuel. Depending on the bottle rocket's materials and strength, you can create a variety of homemade bottle rocket fuels to propel your spaceship into the sky. Always have adult supervision, wear protective eyewear and launch your rocket outside and away from neighbours' homes.
Water, along with pressure, provides bottle rocket jet propulsion. Build your water-fuelled bottle rocket using an empty 2 litre (68 fl oz) plastic bottle, a bicycle pump with an air gauge, an inflating needle (one you might use to inflate a soccer ball), water and a rubber stopper. Punch the inflatable needle through the rubber stopper and attach the needle to the pump. Drill a hole in the bottle, large enough to fit the rubber stopper. Pour 237 ml (1 cup) of water into the bottle then plug the bottle with the stopper. Pump air into the bottle and you'll see air and water (the fuel) forced down through the bottle's neck. This force will propel the bottle upward.
Standard rubbing alcohol, otherwise known as isopropyl alcohol, can be used to launch a bottle rocket. Rubbing alcohol contains the propellant methanol, a powerful and potentially dangerous substance when used at full strength. Attach a straw to the side of a 2 litre (68 fl oz) plastic bottle that acts as the rocket's frame. Drill a 1 cm (3/8 inch) hole in the bottle cap to serve as the rocket's nozzle. Add two or three drops of rubbing alcohol to the bottle and shake vigorously to mix the air and the alcohol. Slide the rocket into the launch rail and place an igniter near the nozzle exit. Light the igniter and watch how the ignited mixture creates pressure, sending the rocket into the air.
Baking soda and vinegar
Use household baking soda and vinegar as bottle rocket fuel. Create your bottle rocket using an empty plastic film container, baking soda and vinegar. Pack the film container tightly with baking soda and add 2 tsp of vinegar. Tighten the lid on the container and place it on the ground upside down. Within a few seconds, the container will shoot up in the air -- possibly as high as 30 m (100 feet).