Rocket Project Lab Report

Kristian Fadrigon

11/6/15

Period 4

Rocket Project Lab Report

Materials and Approximate Price:

• Two 2-liter soda bottles ($1.79 each)
• A pack of cotton balls ($0.97)
• A pack of rubber bands ($0.49)
• Duct tape ($2.00)
• Scissors (no purchase necessary)
• Cardboard (no purchase necessary)
• Garbage bag (no purchase necessary)
• Single-hole punch ($0.91)
• Parachute cord ($4.88)
• A piece of paper (no purchase necessary)
• One egg (provided)
• A rocket launcher (provided)
• Total amount spent: $12.83

Procedure:

1. First, acquire all the listed materials. 
2. Cut off the bottom of one of the soda bottles. 
3. Using the duct tape and the piece of paper, make a cone about half the height of the bottle and secure to the top of the bottle, making the nose of the rocket. 
   
4. Next, cover the walls of the inside of the rocket with cotton balls about two layers thick.
5. Leave a space in the middle for the egg to be placed.
6. Take a few rubber bands of similar size, and attach them to the inside of the rocket, forming a cross above where the egg will be placed. 
7. To make the parachute, first cut the parachute cord into five pieces of equal length, preferably around 1-2 feet.
8. Cut out a circular piece from the garbage bag and hole punch five holes equidistant along the circumference.
9. Tie one end of the parachute cords to each of the holes, and tie the other ends together. 
10. Attach the conjoined ends to the rubber band cross inside of the soda bottle. 
11. Fold the parachute neatly so it fits comfortably in the passenger compartment of the rocket.
12. Next, cut out five fins for the rocket using the cardboard, with three fins for the fuselage of the rocket and two fins for the passenger compartment of the rocket. 
13. Attach the fins to the rocket.
14. Take the untouched soda bottle and place it in the opening of the passenger compartment of the rocket.
15. With the rocket completed, test the rocket to ensure the parachute deploys properly.
16. On launch day, fill a quarter of the untouched soda bottle with water. 
17. Place the egg in the passenger compartment.
18. Again, carefully fasten the two bottles together as to not prematurely break the egg.
19. Place the fuel bottle of the rocket onto the launcher. 
20. Pump the air in the launcher to about 70 pounds per square inch.
21. Countdown from three and pull the string that launches the rocket.
22. Observe its height and record the time it takes to reach its apex.
23. Once the rocket lands, check to see if the egg survived. 
24. Record your results.

Results:

Unfortunately, our group's rocket did not work the way we thought it would. Compared to the rest of the class' rockets, our rocket achieved a relatively low height of around 45 feet, and the time it took to reach the top of its trajectory was only 1.78 seconds. Additionally, the passenger compartment of the rocket did not detach and the parachute did not deploy, leading to the untimely demise of our "eggonaut." However, this was not surprising, since about half the class' parachutes did not deploy even though their rockets flew higher. One thing that I noticed as our rocket was in mid-flight was how heavy the rocket looked. Flying through the air, rocket looked as if it was unable to go higher than it did because of the amount of duct tape we used to make and secure the nose and fins of the rocket. The weather was ideal for flying, so I think no other factors contributed to the inability of our rocket to work except manufacturing errors. 

Conclusion:

In hindsight, there are several things I wish we had changed about the design of our rocket. First of all, I would have changed the size of the rocket's nose and the amount of tape used to secure it. I believe the weight of the rocket came mostly from the passenger compartment, especially the nose. If we had reduced the weight in the passenger compartment, our rocket definitely would have risen higher and faster to its peak. I would also change the fins from cardboard to something thinner and lighter, like plastic. On the inside, I would have put more cotton balls to soften the blow to the egg when it reaches the ground. Although we thought the rubber bands would act as a shock absorber when the rocket impacted the ground, that was only if the parachute properly deployed, which it did not. Overall, if I could do anything to make our rocket better, it would be making it lighter and slimmer.

Calculations:

Force Body Diagrams:

Video of Rocket Launch (Takeoff is around 1:17):