Overview:
For our physics project, our goal was to build a soda bottle rocket ship with an egg in a capsule that would end without suffering any harm while getting a parachute to deploy. Below, we have detailed out process, launch data, results, and some pictures to document our project.
Materials:
Materials were divided into three segments based on where we put them on the rocket.
Main body:
- 1 2-liter bottle, 3 3D printed fins
Egg capsule:
- 1 top half of a 2-liter bottle, 1 cone folded from paper, many cotton balls, 1 small plastic water bottle cut to hold egg, duct tape, masking tape, baby powder, newspaper
Parachute:
Parachute:
- Garbage bag, duct tape (for reinforcing corners), string, paperclip
Procedure:
1. Gather materials listed above
2. 3D print 3 fins (Or create your own out of cardboard)
3. Glue the fins on to a whole soda bottle. Add masking tape for extra insurance
4. Take the second bottle and cut the last ⅓ of it off, it will house the capsule for the egg
5. With string and a garbage bag that is cut in a square, fold the bag into eighths as shown in the video below. Cut along the line, add strings and duct tape. This will be the parachute.
- https://www.youtube.com/watch?v=TrWMO4ewJg0
6. Put an egg in water bottle with cotton balls (or any material that serves as good padding). Put smaller water bottle in top capsule and surround it with newspaper. Attach it to the main body.
*Before attaching the pieces should look like this:
1. Gather materials listed above
2. 3D print 3 fins (Or create your own out of cardboard)
3. Glue the fins on to a whole soda bottle. Add masking tape for extra insurance
4. Take the second bottle and cut the last ⅓ of it off, it will house the capsule for the egg
5. With string and a garbage bag that is cut in a square, fold the bag into eighths as shown in the video below. Cut along the line, add strings and duct tape. This will be the parachute.
- https://www.youtube.com/watch?v=TrWMO4ewJg0
6. Put an egg in water bottle with cotton balls (or any material that serves as good padding). Put smaller water bottle in top capsule and surround it with newspaper. Attach it to the main body.
*Before attaching the pieces should look like this:
Model of our fix for the parachute:
Results:
Our rocket performed adequately. In our first test, we achieved a height of over 75 feet without the parachute deploying leading to the egg cracking. In our second test, our rocket only reached 66 feet but our parachute did deploy and our egg was safe. From our first trial to our second trial, we decided to sacrifice some height in order to make the parachute more easily deploy. With our first attempt, we had an equipment malfunction in that there was too much force and friction being pressed onto the parachute and it ended up not deploying. During our second run, we loosened up the pressure on the parachute with the way we placed the parachute in the rocket and lowered the friction using baby powder. User error was in play with the way the rocket was assembled with each launch. If the parachute was crumpled in a different way, that could have affected our results. Also, the amount of water being placed in the bottle and how the rocket was set up and the launch was affected by human error. The weather may have affected our results as the wind could have increased air resistance.
Our rocket performed adequately. In our first test, we achieved a height of over 75 feet without the parachute deploying leading to the egg cracking. In our second test, our rocket only reached 66 feet but our parachute did deploy and our egg was safe. From our first trial to our second trial, we decided to sacrifice some height in order to make the parachute more easily deploy. With our first attempt, we had an equipment malfunction in that there was too much force and friction being pressed onto the parachute and it ended up not deploying. During our second run, we loosened up the pressure on the parachute with the way we placed the parachute in the rocket and lowered the friction using baby powder. User error was in play with the way the rocket was assembled with each launch. If the parachute was crumpled in a different way, that could have affected our results. Also, the amount of water being placed in the bottle and how the rocket was set up and the launch was affected by human error. The weather may have affected our results as the wind could have increased air resistance.
Videos for rocket:
Two angles of the same launch.
Diagrams/Pictures:
Calculations:
- Calculate upwards acceleration and height of rocket at apogee
The camera moved 14% from the time the rocket was launched to the time that the rocket reached its apex. Therefore, we multiplied all distances and velocities from LoggerPro by .86 to get a more precise value. Read about this more in the conclusion.
2) Calculate downwards acceleration
3) Calculate force of thrust
4) Free Body Diagram
a. FBD of liftoff
b. FBD of rocket just starting to fall down and FBD of rocket falling with parachute
Conclusion
Overall, the rocket fared very well and passed our expectations. When we constructed our rocket, the hot glue melted a small part of the rocket body, so one of the wings was a little out of place. To make our rocket better, I would have made the wings bigger and added another one. In all of our runs, the rocket would go fairly high but would wobble at its apex because the wings would not stabilize the bottle. Some of the other groups had four big cardboard fins that made their ship go high. If the wings are too light, then it won’t stabilize, but if it is too heavy, it will not go high enough. The cardboard seems to serve as a good medium. The size of the bottle was good because the top was slightly bigger than the base, so it detached easily. Some other groups had very slim bottles, but it would not detach. I would not change the size or shape of the bottle. The weather was somewhat ideal because there was not much wind. However, the air was very dense and wet. If the weather was more dry the rocket would be marginally better. It is like a baseball; on a warm day a ball will carry more, however, it will drop faster on a wet day. The Giants play near the water, and because of the dense air near the ocean, the ball is known to not carry very well. With the air less dense, the rocket, like a baseball, will go further and higher. Another issue we had was the capsule detaching. The bottle was loose, but the capsule would detach late and the parachute would not come out. We used baby powder to lessen the friction between the capsule and the main rocket body. Although we got the capsule to come out faster, the parachute did not come out during the test runs. I tried to put the parachute in the capsule in a way that would make the parachute come out with the downwards pull from the apex. However, there was not nearly enough pull to make this happen. The only way it would have worked that way would have been if there were holes to push the air through so the parachute would deploy. In order to fix the problem, we used a paperclip. The paperclip was attached to a string on the capsule and then the other side hooked on to the body. The idea was to have the end of the clip loosely attached to the main body. The tug would create separation. As the capsule pulled on the body, the parachute was pulled out early enough to allow air to enter under the parachute to open it. In the end, we did have errors that affected our calculations. From the time that the rocket took off to the time that the rocket reached its vertex, the camera shifted position by about 14%. This shift affected our calculations for height, as it caused LoggerPro to overestimate the upward velocity of the rocket by 14%. Accounting for this change, we should multiply the calculated height by .86, resulting in 71.1 feet, a value much closer to our actual launch height than calculated. The remaining few feet over can be attributed to the fact that our rocket did not go straight up. It went sideways a few feet, causing our numbers to be inaccurate. On the way down, the camera moved a lot. This greatly affected our data on LoggerPro, meaning that our downwards acceleration data above is wrong. If we were to do this lab again, we would make sure that our camera is propped up so that human error will not cause it to move and mess up the frame.
Overall, the rocket fared very well and passed our expectations. When we constructed our rocket, the hot glue melted a small part of the rocket body, so one of the wings was a little out of place. To make our rocket better, I would have made the wings bigger and added another one. In all of our runs, the rocket would go fairly high but would wobble at its apex because the wings would not stabilize the bottle. Some of the other groups had four big cardboard fins that made their ship go high. If the wings are too light, then it won’t stabilize, but if it is too heavy, it will not go high enough. The cardboard seems to serve as a good medium. The size of the bottle was good because the top was slightly bigger than the base, so it detached easily. Some other groups had very slim bottles, but it would not detach. I would not change the size or shape of the bottle. The weather was somewhat ideal because there was not much wind. However, the air was very dense and wet. If the weather was more dry the rocket would be marginally better. It is like a baseball; on a warm day a ball will carry more, however, it will drop faster on a wet day. The Giants play near the water, and because of the dense air near the ocean, the ball is known to not carry very well. With the air less dense, the rocket, like a baseball, will go further and higher. Another issue we had was the capsule detaching. The bottle was loose, but the capsule would detach late and the parachute would not come out. We used baby powder to lessen the friction between the capsule and the main rocket body. Although we got the capsule to come out faster, the parachute did not come out during the test runs. I tried to put the parachute in the capsule in a way that would make the parachute come out with the downwards pull from the apex. However, there was not nearly enough pull to make this happen. The only way it would have worked that way would have been if there were holes to push the air through so the parachute would deploy. In order to fix the problem, we used a paperclip. The paperclip was attached to a string on the capsule and then the other side hooked on to the body. The idea was to have the end of the clip loosely attached to the main body. The tug would create separation. As the capsule pulled on the body, the parachute was pulled out early enough to allow air to enter under the parachute to open it. In the end, we did have errors that affected our calculations. From the time that the rocket took off to the time that the rocket reached its vertex, the camera shifted position by about 14%. This shift affected our calculations for height, as it caused LoggerPro to overestimate the upward velocity of the rocket by 14%. Accounting for this change, we should multiply the calculated height by .86, resulting in 71.1 feet, a value much closer to our actual launch height than calculated. The remaining few feet over can be attributed to the fact that our rocket did not go straight up. It went sideways a few feet, causing our numbers to be inaccurate. On the way down, the camera moved a lot. This greatly affected our data on LoggerPro, meaning that our downwards acceleration data above is wrong. If we were to do this lab again, we would make sure that our camera is propped up so that human error will not cause it to move and mess up the frame.
Who did what:
Grant: Results, Fins
Zack: Calculations, parachute
Noah: Materials and Procedure, FBD, Egg capsule
Mason: Materials, Main body
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