Design Reasons/Process

1. We chose a 40 degree angle, looking for a balance between lift and initial velocity. In a vacuum (or on the moon), the angle might be a perfect 45 degrees because the ball would travel in a perfect parabola. Instead, the ball travels in a different pattern.

2. The chamber in the bottom was placed there for three reasons: The first to create a place where the ethanol could have a higher concentration. The second was so that we could make our cannon's barrel shorter, and the third was so that it could build up more pressure in the chamber before it was released to the Nerf ball.

3. The second can plays no part in the chemical reaction-- it is just there to stabilize the first can, where the explosion actually occurs.

4. The chemical formula for ethanol is C2H5OH. The reaction that occurs is a combustion reaction-- the ethanol and oxygen in the air combust in reaction to heat and produce water and carbon dioxide:

C2H5OH + O2 -----> H2O + CO2


5. Gay Lussac's law states that temperature and pressure are directly proprtional to each other-- when the temperature rises, so does the pressure and visa versa. When the ethanol in the tennis ball can ignited, the temperature rose sharply and so did the pressure. The only outlet for that sharp rise in temperature was the weakes link: the nerf ball.


6. The launch formula:




R= distance projectile goes through the air= 0
V= the initial velocity= 0
Theta= measure of the lunch angle= 40 degrees
g= gravitational constant= about 32.2 ft/sec


We were not sure what we expected the cannon to do, although there were three probable options:
1. The cannon would launch the Nerf ball (hopefully!)
2. The back chamber of the cannon would shoot backwards (if the weakest point
of the barrel was the place it was taped together as opposed to the end
where
3. An exo-thermic reaction would take place and the cannon would melt as a result of not enough pressure to blow off the Nerf ball.
the Nerf ball was stuffed in)