Elements of our Cannon

Plan of Design: We choose a simple design, where we would cut the end off of one tennis ball can (the cap is closer to bottom) then use the other can as our base. The cannon barrel will be positioned on the base so it is at a 45 degree angle. We poked a small hole in the lower side of the bottom of the barrel. This hole will serve as the entrance to lighting the ethanol in the cannon. We decided to cut along our barrel & then try to make it more narrow by overlapping the parts & taping it airtight. 

Launching Angle: We chose to launch our cannon at 45 degrees because it will shoot the nerf ball up pretty high but also launch it out pretty far. Hopefully, this angle will send the nerf ball really far! (The objective is to shoot furthest.) When we did research, we got that anywhere between 35 and about 50 were the optimum angles to shoot from.

Gas Law Used: We used Gay-Lusaac's law that says the pressure of gas is proportional to temperature (in kelvin) if the volume is held constant. So if the temperature goes up, the pressure goes up; if the temperature goes down, the temperature goes down, as long as the volume is constant. When the ethanol is light, the temperature in the cannon will quickly rise, creating the nerf ball to shoot out of the cannon barrel. 

Chemistry Reaction: 

C₂H₅OH + 3O₂ --> 2CO_{2+ 3H2O}

The CO2 will gain pressure in our cannon barrel & launch the nerf ball.

Difficulties In Construction?

We didn't have any difficulties when we were constructing our cannon, besides being worried if it was air-tight. We don't want any of the ethanol gas escaping because then the pressure can't build up & send our nerf ball flying!