Water Bottle Rocket Summary/Reflection

For our rocket, we cut the top off of a 2-liter soda bottle and attached it to the bottom of a second, complete bottle. We at first added cardboard fins to help the aerodynamic aspect of the launch and 20g weights to the bottom of our rocket to ensure that it would fly with the parachute on top. Yet after multiple trials, the cardboard fins started getting beat up and flimsy and the weights on the bottom were causing the rocket to fall too fast through the air. Therefore we ended up taking both design features off. For our parachute, we had two designs. The first design had slits to create the four corners of the parachute and we made loops at the end in which to attach the parachute to the rocket using thin rope. Once fully expanded, this parachute looked similar to a grocery shopping bag flying through the air. (with handles) The second design was a double-layered square with the four corners tied down to the bottle. Though we used the first design for all of our practice launches, when it came to launch day we ended up liking the square parachute a lot better. We then capped the rocket with a cone at the launch, which helped with the aero dynamicity of it and once it started to descend, the cone flew off and the parachute deployed. 

On launch day, we quickly discovered the endless list of things that could go wrong with each launch. Many times our rocket would fly super high but then the cone would get stuck on the bottle and the parachute wouldn’t deploy. At other times, we had too much or too little water so the amount of fuel wasn’t right. At other times, the pump would be really tight so it was hard to get the right air pressure and so when we were tired we would just give up and launch it. And sometimes, water would leak from the stopper and the rocket wouldn’t launch as high. As you can see, many things can go wrong with each launch so it was very frustrating to try and get everything just right.

By doing this lab, I learned about aerodynamic design and structures. Trying to make our rocket as aerodynamic as possible, we tweaked our structure many times. This got me thinking about aerodynamic structures in real life such as bullet trains. Because I am thinking of it in a physics manner, I realize now that bullet train's structure are designed for its aero dynamicity, as the nose can cut through air and walls are smooth, with nothing that will add air resistance.