Jared Frank, Vince Feliciano, Arturo Gamboa-Gonzalez
AP Physics 1
Bottle Rocket Lab
Part 1: Pre-Experiment
- Materials & Procedure – List everything used! Include pictures! How did you construct your rocket?
- 2 2-liter bottles
- Duct Tape
- Marshall’s Thin Bag
- Ziploc Bag
- Orville Popcorn
- Hard-Boiled Egg
- Cut a 2-liter bottle in half, around the diameter. This will act as the egg capsule.
- Cut out 4 fin-shaped cardboard pieces, and attach them around the whole 2-liter bottle, each 90 degrees apart.
- Smooth any rough edges on the fuel cell with duct tape so that it travels upward easier.
- Fill a ziploc bag with popcorn. Place it inside the capsule.
- Cut the Marshall’s thin bag so that it can act as a parachute for the capsule.
- Tape one side of the thin rope onto the edges of the parachute, the other onto the edge of the capsule.
Part 2: Experiment
Note: Because our rocket flew higher during our first launch when our video file didn’t work, we used the initial velocity and mass values for that launch in our data; the time values, however, come from our second launch shown in the attached video.
Time from rest to acceleration (2nd launch): 0.24 s
Time from acceleration to peak(2nd launch): 1.30 s
Time from peak to ground (2nd launch): 4.20 s
Initial velocity (1st launch): 53 km/hr = 14.7 m/s
Mass (1st launch): 1.129 kg
Left FBD is the rocket when it lifts off the ground, right FBD is the rocket when it starts to fall down.
- Results – How did your rocket perform? Be specific, Compare with others, What factors (weather, user error, equipment malfunction) were present?
Results: Our egg ended up flying 37.4 feet. Our rocket separated at 1.54s, and as the body of the rocket barrelled down, the nose cone with the egg slowly glided down at -1.28 m/s^2. This acceleration is significantly less than that of gravity, -9.8 m/s^2, which goes to show how successful our parachute was in creating enough drag to slow the nosecone down enough to protect the egg. The cushioning from the popcorn also reduced the effects of the impact on the egg, leaving our eggonaut unharmed!
Error: As noted earlier, we combined data from two different launches, which most likely resulted in values different from the actual height and time of the launches. Our rocket’s low height compared to our initial launch (in which our video file didn’t work) can most likely be attributed to the different rocket launcher. Many of the groups who launched rockets before and after ours also didn’t quite reach the height other groups had reached with a different launcher a few days before. In addition, our rocket might have separated too early because the nose cone was placed on top of but not attached to the body, which meant that the momentum resulting from the initial thrust force was distributed between the nosecone and the body too early.
Part 4: Conclusion – What could have made your rocket better? Size, Shape, Weather, What would you change?
To make our rocket perform better, our group should have lengthened our rocket to ensure more stability. During our launch, our rocket tilted to the side a little bit, so if the rocket stayed completely upward, it most likely would have traveled higher. In addition to the length, we could have patched the rough edges on our rocket better. Without the rough edges, we would have neglected a lot more air resistance, so the acceleration would have been closer to -9.8. Regarding the egg, we protected our egg pretty well, as it survived every launch.