Law of Action and Reaction / reaction Newton's Law I begin from propulsion to reaction. 
     The water rocket also flies by means of the propulsion to reaction. It flies taking advantage of a resultant reaction of the water that is being expelled by the compressed air that it transports. The school texts treat the topic of water rockets as an extended example of action and reaction, explaining that " a water rocket is promoted ahead by a force of reaction generated by the liberation of air compressed inside the body of the rocket, which provokes the expulsion of the water across the mouthpiece.

Law of Conservation of the Momentum. 

    Mass multiplied by equal speed "momentum". It expresses by means of the equation:
Momentum=masa × speed.
      Every object has tendency to support a constant momentum before and after a movement. This is known as the " Law of Conservation of the Momentum ". Here we will mention and apply this law to explain the physics of the rockets. In altars of the simplicity, we will presuppose that a rocket in rest has certain mass: Mass = M + m, where "M" is the mass of the body of the rocket and "m" is the mass of the fuel. The rocket burns his fuel in an instant and expels gas backward with a mass "m" to a speed "Sees".It is the speed that the rocket has acquired by means of the expulsion of the fuel (supposing that the resistance of the air = 0) .Como the speed of the rocket before throwing the fuel is 0, the momentum is certainly 0. The momentum of the fuel "p" expelled expresses to himself like p = m × (-it sees), and the momentum "P" of the rocket that has started moving due to the force of reaction expresses to himself like P = M × V. This way, the total of the two momentum is: P + p = MV - mVe. With this equation, the symbol less ' in - mVe means that the direction of the expelled fuel is opposite to the direction towards which the rocket moves.

Chemical Talves
      The water rockets do not use any chemical reaction but they acquire push using air pressurized to throw the water towards out. As such, it might say that they fall down inside the category of not chemical rockets. On the other hand, the water rockets have also something jointly with the chemical rockets, since they fly generating a relatively strong push in a short period of time. In other words, the water rockets suffer a process of conversion of energy: energy for compression of the air, kinetic energy of the air (expansion), kinetic energy of the water (expulsion), while the chemical rockets happen for a process of chemical energy to heat energy to kinetic energy.

Aim Of Accomplishment of the Project
     Nowadays, the construction of water rockets has a wide range of applications, of educational programs in schools and colleges to community events and other initiatives, which goal is to interest the students and small children in the science. The water rocketry is a really attractive topic for the children. Los cohetes pueden despertar y desarrollar su curiosidad, ampliando los horizontes de su aprendizaje y experiencia más allá de la ciencia. En la etapa inicial, el interés de los niños se centrará en cuán lejos pueden volar sus cohetes. Luego empezarán a pensar en lo que pueden hacer para mejorar el desempeño del vuelo. En el proceso de poner en práctica su ingenio y lograr sus objetivos, adquirirán la habilidad para resolver problemas. Además, pueden experimentar un gran sentido de logro y satisfacción luego de haber construido con éxito sus propios cohetes.