Wednesday, December 10, 2003
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IV: EC: How Rockets Fly

Fist of all, we must understand that ΔH is positive and the reaction is an endothermic as heat is added to the fuel to create gases as their products. Then we can assume that the amount of gases has increased after the reaction begins to occur. Then, we can use Avogadro's Law(1) which states, “If the amount of gas in a container is increased, the volume increases.” So now we know that ΔV is positive also. Then we can apply Charles’ Law(2) which states, “If the volume of a container is increased, the temperature increases.” Therefore, we can conclude that ΔT is positive. Then we use a part of the Kinetic Molecular Theory(3) which states, “The average kinetic energy of all the molecules is proportional to the absolute temperature.” Since ΔT is an increase, then the average kinetic energy of the molecules would proportionally increase with it. Then we can use another part of the Kinetic Molecular Theory(4) which states, “The tiny particles in all forms of matter are in constant motion.” We also need another part of the Kinetic Molecular Theory(5) which states, “Molecules collide with one another and the sides of the container.” We then use Newton’s First Law of Motion(6) which states, “Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.” This shows us that the gas molecules and their average kinetic energy are constantly moving until they are stopped by and external force, which would be the collisions with the sides of the container or the motor case. This would eventually direct motion of the molecules and energy toward the opening of the motor case which is not an external force which stops motion. We then can apply Newton’s Third Law of Motion(7) which states, “For every action there is an equal and opposite reaction.” This equal and opposite reaction would the opposite of the kinetic energy of the gases headed toward the ground which would create the energy needed for the thrust and launch of the rocket to send it into flight.

Sources
1 http://dbhs.wvusd.k12.ca.us/GasLaw/Gas-Avogadro.html
2 http://dbhs.wvusd.k12.ca.us/GasLaw/Gas-Charles.html
3 http://dbhs.wvusd.k12.ca.us/GasLaw/Basics-of-KMT.html
4 Chemistry Fourth Edition, Addison-Wesley
5 http://dbhs.wvusd.k12.ca.us/GasLaw/Basics-of-KMT.html
6 http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html
7 http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html

Stephen at 10:20 PM