1. Materials:
2x plastic bottles of seltzer water- $2.50
2x styrofoam meat packing trays- Free (comes with meat)
2x plastic bottles of seltzer water- $2.50
1x piece of printer paper- $0.99
1x Styrofoam- $1.00
1x baby bottle candy plastic cover- $1.00
1x raw egg- $0.13
1x plastic garbage bag- $0.31
9x pieces of string 1.5 feet long- $0.23
2. Procedure:
- Step 1: Using a X-acto knife to cut off the bottom of the 2 liter bottle where there is a indented line at the bottom of the label.
- Step 2: Trace an outline of a fin on a piece of paper and cut it out.
- Step 3: Use the outline of the fin to draw 4 fins on the 2 styrofoam meat packaging trays (note: the bigger the fins, the more stable your rocket is, and the more stable your rocket is, the straighter the trajectory going up.
- Step 4: Poke a hole in the bottom of bottom section of the bottle that was cut out in Step 1.
- Step 5: Run all 9 pieces of string through the hole so that there is an equal length of each string sticks out.
- Step 6: Tie a knot with the ends of the string sticking through the hole, make the knot big enough that it can not slip through the hole you made.
- Step 7: Cut out a big circle from the plastic garbage bag, this will be your parachute. The circle can be whatever size you want. (Note: the bigger the parachute, the slower the descent of your egg.
- Step 8: Glue the nine end points of the nine separate ends of the strings to nine even spaced points on the circumference of the circle.
- Step 9: Take the piece of printer paper and roll it into the shape of a cone, and tape the edges of the paper lengthwise along the roll
- Step 10: Place the plastic bottle cap of the baby bottle candy over the point of the rolled up piece of paper and tape it in place. These two pieces will be your rocket tip.
- Step 11: Tape the rocket tip to the top of the bottle which had it’s bottom cut off.
- Step 12: Stuff some small styrofoam pieces towards into the upper body section of the rocket so the styrofoam touches the opening of the bottle. This will act as padding for the egg.
- Step 13: Encase the egg in styrofoam and push it into the open body of the upper section. Push the styrofoam encased egg until the styrofoam touches the small piece of styrofoam placed inside as cushioning.
- Step 14: Take the cut out bottom of the bottle with a parachute attached, and push it inside the upper body section of the rocket with the top of the parachute facing the opening of the upper body section of the rocket. Secure the bottom of the bottle to the inside of the rocket body with many strips of tape.
- Step 15: Carefully fold your parachute and lightly push it into the remaining space left in the upper body portion of the rocket. Make sure the central point of the parachute is not folded inwards or tangled. This will ensure the parachute opens properly if the rocket separates properly.
- Step 16: Take the other bottle that has previously been untouched and fill it with 6 ounces of water and cap it. Stand the bottle on its capped bottom and use a sharpie to draw a line around the water line.
- Step 17: Using the drawn line, attach your four cut out fin pieces with the points facing upwards and the flat side of the triangle rests on the bottle’s surface. Secure the fins with copious amounts of tape to ensure the fins are rigidly held in place and do not bend or flap around.
- Step 18: Finally, place the two separate part of your rocket together so that upper body section of your rocket fits over the the bottom of the bottle with fins attached. Make sure your parachute does not get trapped between the two bottles otherwise this could damage it as the rocket separate and the parachute deploys.
- Step 19: Do several practice launches and make adjustments to your rocket as needed.
- Step 20: Pray for good conditions on the final rocket launch day.
3. Launch & Results:
The rocket performed decently. It launched very successfully, reaching a greater height than any of the other rockets, however it failed to separate and deploy the parachute. The egg cracked because of it. Others had proper separation and their parachutes deployed successfully. My rocket had a squished nose cone because of the harsh landing. Overall, factors that accounted into the launch's failure are weather, human error, and weight.
4. Conclusion:
There are several things that could have made the rocket better. In connection with the factors listed in the “Results” section of this write up, the effects and improvements relating to the factors are listed here. The weather factor that was present was wind. The wind blew the rocket off course a little and prevented the rocket from reaching an altitude it could have reached if it had gone straight up instead of in an upwards, diagonal line. The human error is that in order to facilitate separation, WD-40 was used to try to lubricate the sections where the rocket portions went over each other. However, it is likely that the force of the acceleration upwards combined with the lubrication of the rocket pieces caused the upper body and lower body to slide further inwards thereby make separation nearly impossible. The factor of weight could have also helped separation. Placing extra weight in the tip of the nose as ballast may have helped the rocket fly on a less diagonal course and also help the rocket during its separation stage. One thing I would change for my rocket is adding on fins to the nose portion of the rocket to act as drag and provide more air resistance as the rocket goes up and down. This slows the egg down and results in a lower height. Since the height is lower, if there is no separation and no parachute deployment, the egg has a higher chance of surviving a crash from a lower altitude than a higher one.
6. & 7. Calculations:
8. Force Body Diagrams:
