Introduction - Problem and Hypothesis

          From the first Chinese ingenuities to the epoch of the Space Age, the rocket has, both literally and symbolically, taken the world to great heights. There are many different types and utilizations of rockets. The first rockets, invented in 1232 by the Chinese, were used as fireworks (and later as weapons). Rockets have been used to launch satellites, telescopes, and astronauts into space. They have incited national competitions as well as global unity. Behind the flight of a rocket is a baroque field of physics and engineering. In this study, I will examine the effects of ambient pressure, internal pressure, and propellant volume on the apogee of a water and compressed air powered rocket.

My hypothesis is that increased air pressure, lower ambient pressure, and greater water volume will lead to increased apogees. An increase in air pressure inside of the rocket will lead to a higher apogee because the greater potential energy will cause a greater force when the rocket is launched. Lower ambient pressure will lead to a higher apogee because, according to the thrust equation , thrust is proportional to  mass flow rate, exit and ambient pressures, and exit area. Therefore, lower ambient pressure will lead to more thrust and higher apogee. Greater water volume will lead to a higher apogee because it will cause a greater full mass (mo). According to the payload mass ratio , a greater value of mf will lead to a greater payload mass ratio . The payload mass ratio is also used in the Tsiolkovsky Rocket Equation. The change in velocity would be increased by a higher mass ratio. Consequently, a greater volume of water will lead to a higher apogee.