Waterrocket is a kind of model rocket that uses water as means of itsreaction mass. The rocket has a pressure vessel which serves as itsengine and in most cases is made out of plastic bottle (Watanabe,Tomita & Takemae, 2003). Water inside the bottle is forced outby mass of gas under pressure, which is mostly same as compressedair. The water rocket is thus said to operate mainly on the basis ofNewton’s third law of motion which states that action and reactionare equal and in opposite direction (Bollen, Hoppe, Milrad, &Pinkwart, 2002).
Inthe 1960s there was importation of water rocket toys by Japan fromGermany and the United States and later in the mid-1980s, waterrocket competitions were done in Scotland (Güémez, Fiolhais &Fiolhais, 2009). In 1974, the PET bottles used as water rocketmaterial were first employed (Fujii et al, 2009). The issue wouldthen be addressed by “Mother Earth News” in August 1983 (O`rourke& Teepell, 2001). Currently, the making as well as launching ofwater rockets is done in different forms and in different parts ofthe globe. Even though the US is known for water rocket making, otherpopular areas where they are made include schools and science museums(Sutton, 2003). In July 3, 1998 Bruce Berggren is the first to flythe two stage water rocket Mark VII to 1060’ (Mitlitsky et al,1999). However, in May 2001, water rocket toys are recalled. Later in2002 Robert Youen sets the new water rocket world record at 1150’while using CO2 at 130psi (Jarvis & Pell, 2005). In July thefollowing year, Ken Schellenberg achieved a world record using acarbon fiber rocket named A37 at a height of 1242’. In 23rdOctober 2004, the X-10 rocket by US Water rockets set a new record of1606 feet (Lin, 2005). In April 2005, the US would break theirprevious record at 1609 feet. Again a month later, on 26th,the US breaks their record at 1696 feet (Perkins et al, 2006). Thefollowing year in September 24th,U.S Water rockets would set a new record with their X-12 rocket at1,715 feet. The records would then be broken until the latest in 2006by a rebuilt X-12 rocket at a height of 1787 feet.
Theprinciples of water rockets are related to that of actual or realrockets (Tomita, Watanabe & Nebylov, 2007). The real rockets areknown to use gas or other vapors when launching, but water rockets onthe other hand use water. The principle of action reaction law forgas, vapors and water applies in their operations (Prusa, 2000). Inwater rockets, water is like fuel as it plays the role of fuel andthrough consistent and continuous release the air becomes pressurizedand therefore is transformed into energy (D`Andrade & Johnson,1995). Given that the air density is low, it therefore becomes mucheasier to pressurize and thus a lot of air fuel is stored inside thePET bottle. Upon leaving the bottle, the air expands at a high rate,thus prohibiting the water rocket from flying to far distance(Thorncroft & Pascual, 2005).
Theliquid used in our case which is water has an advantage given that itdischarges in one specific direction even though pressurizing itbecomes difficult (Redfield, 2006). Owing to the characteristics ofair and water, the non-pressurized liquid thus attains a highpressure from the vapors. Consequently, this is then promptlyreleased to generate a push or thrust force (Watanabe, Tomita,&Takemae, 2003). At the same time, the rocket receives energy in formof motion relative to the amount of energy discharged in the oppositedirection.
Bollen,L., Hoppe, H. U., Milrad, M., & Pinkwart, N. (2002, July).Collaborative modelling in group learning environments. InProceedings of the XX International Conference of the System DynamicsSociety. Palermo (Italy).
D`Andrade,B. M., & Johnson, L. G. (1995). U.S. Patent No. 5,415,153.Washington, DC: U.S. Patent and Trademark Office.
Fujii,H. A., Watanabe, T., Kojima, H., Oyama, K. I., Kusagaya, T.,Yamagiwa, Y., … & Trivailo, P. M. (2009). Sounding rocketexperiment of bare electrodynamic tether system. Acta Astronautica,64(2), 313-324.
Güémez,J., Fiolhais, C., & Fiolhais, M. (2009). Toys in physics lecturesand demonstrations—a brief review. Physics Education, 44(1), 53.
Jarvis,T., & Pell, A. (2005). Factors influencing elementary schoolchildren`s attitudes toward science before, during, and after a visitto the UK National Space Centre. Journal of Research in ScienceTeaching, 42(1), 53-83.
Lin,C. (2005). U.S. Patent No. 6,957,526. Washington, DC: U.S. Patent andTrademark Office.
Mitlitsky,F., Weisberg, A. H., Carter, P. H., Dittman, M. D., Myers, B.,Humble, R. W., & Kare, J. T. (1999, September). Waterrocket—Electrolysis propulsion and fuel cell power. In AIAA SpaceTechnology Conference and Exposition Spetember.
O`rourke,J. P., & Teepell, T. F. (2001). U.S. Patent No. D438,914.Washington, DC: U.S. Patent and Trademark Office.
Perkins,K., Adams, W., Dubson, M., Finkelstein, N., Reid, S., Wieman, C., &LeMaster, R. (2006). PhET: Interactive simulations for teaching andlearning physics. The Physics Teacher, 44(1), 18-23.
Prusa,J. M. (2000). Hydrodynamics of a water rocket. SIAM review, 42(4),719-726.
Redfield,R. C. (2006). Bond graphs of open systems: a water rocket example.Proceedings of the Institution of Mechanical Engineers, Part I:Journal of Systems and Control Engineering, 220(7), 607-615.
Sutton,G. P. (2003). History of liquid propellant rocket engines in theUnited States. Journal of Propulsion and Power, 19(6), 978-1007.
Thorncroft,G. E., & Pascual, C. C. (2005, January). Hydrodynamic study of awater-propelled rocket: an undergraduate experiment in fluidmechanics. In ASME 2005 International Mechanical Engineering Congressand Exposition (pp. 769-778). American Society of MechanicalEngineers.
Tomita,N., Watanabe, R., & Nebylov, A. V. (2007). Hands-on educationsystem using water rocket. Acta Astronautica, 61(11), 1116-1120.
Watanabe,R., Tomita, N., & Takemae, T. (2003). Thrust Characteristics of and Their Improvement. Japan Society of AeronauticalSpace Sciences, 51, 314-320.