Soda Bottle Rocket Project

The rocket launch project served to demonstrate how momentum, stability, drag, and a recovery system can aid a soda bottle rocket in flying. Though our rocket was not the prettiest, it did the job of utilizing water and compressed air to shoot into the air. Our challenge was to create a rocket that could withstand the force exerted on it during the launch, while making sure it could protect the egg inside of it. We tried changing many things until we created a rocket, cone, fin, and recovery system combination that worked. The overall look of our rocket included a plastic cone on top of a two liter bottle, and 4 fins around the base. Though our rocket
The rocket flew because when the water, pushed into the 2-liter bottle, was released

with compressed air, it was able to shoot through the small opening of the bottle with enormous force. Thrust is the unbalanced force that occurs until all the pressure, water and air, contained in the rocket, is released. When a greater amount of momentum is conserved in a bottle, it will shoot up higher due to the pressure it is discharging. Adding water to the rocket will use the larger mass directed downward to produce a greater impulse, pushing the rocket up. The thrust test was conducted by filling up the rocket with the desired amount of water and pushing it onto a force plate, pumping it with compressed air. When the ring around the opening of the bottle is removed, the rocket shot up from the pipe. The independent variable is time in seconds and the dependent variable is force in Newtons. The constants of this experiment are the bottle and the pressure. The thrust vs. time graph shows the relationship between the force of thrust and the time. The area underneath the graph represent impulse.
This impulse vs. water mass graph shows that adding too much water in the rocket leaves too little of compressed air in the rocket to shoot it upward. Adding too little water doesn’t give the rocket enough force downward to increase the impulse. The area under the graph represents the impulse.
The center of gravity is an imaginary point in a body of matter where, for convenience in certain calculations, the total weight of the body may be thought to be concentrated.

The center of pressure is the point where the total sum of a pressure field acts on a body, causing a force to act through that point. The center of gravity must be above the center of pressure in order for the rocket to work. After consulting the rocket readings, we discovered that as air rushes past the rocket, the larger air resistance forces below the center of gravity than above the center of gravity will help to straighten it out, pushing the tail of the rocket below the nose and producing stable flight. The swing test was a test used to confirm the rocket’s stability. It consisted of someone swinging our rocket around on a string, seeing if it would fall apart. It can also be used to determine how aerodynamic the rocket is. To increase the stability, we made sure the center of gravity was above the center of pressure and we used fins to stabilize our rocket.
We decreased our rocket’s drag by making our cone out of plastic, instead of paper. We refrained from adding too much tape, which would increase the drag. We originally placed the parachute outside of the cone, but realized it would prevent the rocket from reaching the desirable height. Adding fins covered in tape and sculpted in the correct shape kept the rocket arrow dynamic. Because of the changes, drag was

decreased.
The parachute helps recover the egg because as time increases, force decreases. This allows the rocket to fall gently to the ground, instead of crashing down and cracking the egg. The less force the rocket had as it landed, increased the chance of survival the egg had. Padding for the egg protected it by taking in the force, giving the egg more time to land safely. We wrapped our egg in bubble wrap and placed it in a seperate part of the bottle rocket that was lined with cushion stuffing. The light and airy cushion stuffing provided the egg with more time to land. This protection kept the walls of the rocket from slamming into the egg, which would have caused it to break. Our parachute failed to come out on multiple occasions, but our padding for the egg kept it from cracking. We tried making a bigger cone, adding weights to the strings of the parachute, and even made a whole new parachute. Unfortunately, none of our ideas worked, leaving us to solely rely on our egg protection system. Before using cushion stuffing, we wrapped the egg solely in bubble wrap, which didn’t provide enough time for the egg to land safely. With our newly improved recovery system, we were able to protect the egg.
The launches of our rockets all shot up with great force, but most of our launches were not successful. We tried about 10 times to launch the rocket. Each rocket launch reached varying heights. Our last launch reached the desirable height of . Our rocket only survived about half of the launches due to our failed recovery system. Our egg survived about half of our launches, the higher our rocket went, the more likely it was for our egg to break. However, when we improved the egg’s protection with cushion stuffing, the egg survived every launch. Our parachute never worked, while the egg contraption sufficiently protected the egg every launch.
If I could change 3 things about our rocket, I would work to improve the parachute by creating a spring loaded contraption to help release the parachute. Improving our recovery system would help protect the egg, ensuring its safety 100% of the time. I would also make the rocket look nicer and more professional. This would improve others’ perception of our project. I would make our cone out of a stronger material to make the rocket more aerodynamic and better protect the egg upon impact. This would help the rocket shoot up faster and higher. Changing these three things, would significantly improve the performance of our rocket.