Three Facts About Water Rockets

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Building water rockets is an ideal activity for parents, teachers and kids. Water rockets are a good way to teach children principles of physics in a fun, hands-on way, and they give kids the perfect opportunity to make things explode. Knowing the facts about building the best water rocket makes it a fun, educational and safe experience for all.

Decription of a Water Rocket

A water rocket is a corked bottle of water and compressed gas -- usually carbon dioxide. When the bottle cork is no longer able to withstand the pressure inside the bottle, it explodes off and the gas trapped inside forces the water through the nozzle at such a high velocity that the bottle jets into the air until all the gas has escaped. Once that fuel is gone, the bottle begins its descent back down to Earth.


A longer, skinnier bottle works better than a shorter, fatter one because the increased length makes the rocket more stable and moves the center of gravity away from the nozzle and fins. A 2 liter soda bottle is ideal since they are strong (they can usually withstand up to 30 psi) and lightweight. For similar reasons, the fins should be made of paper and as small and far to the back of the rocket as possible to reduce drag.


Rockets were invented by the Chinese in the first century BC. While no one knows who invented the water rocket, its development can be traced. In December 1898 a new invention called a "Toy Boat" used chemically produced gas to propel a small boat. Then in 1962, a patented "Jet Propelled Toy Arraignment" used water and a "water soluble gas generating pellet" for propulsion, and later that year a two-stage water rocket was released.


When working with rockets, safety must always be the top priority. Bruce Berggren, world water rocket altitude record holder, developed the Water Rocket Safety Code. The code directs water rocket users to maintain a safe distance at all times between people and pressurized rockets or launchers; store and transport compressed air tanks and gas cylinders in accordance with all applicable safety codes; hold the launcher within 30 degrees of vertical to ensure nearly straight flight; countdown before launching to ensure spectators are paying attention and are a safe distance away; never use flammable or explosive payloads; launch outdoors in an area with at least 100 ft. of open space (500 ft. for rockets higher pressure rockets); and never rescue rockets from dangerous places.