2-L Rocket Eggmision

3 Questions
1. How should the weight be distributed on the rocket?
2. What happens when the rocket runs out of fuel?
3. What is the best way to protect the egg?

By doing this project, I was able to definitely answer question 2. When the rocket runs out of fuel, it continues to go higher due to the force. Within a fraction of a second, the rocket slows and starts back towards the ground.

Making of the Rocket
Our materials that we used were:
1. 2 two-liter soda bottles
2. cardboard
3. duct tape
5. padding (rolls of cotton ball-ish material?)

A.J. and I did not have a very organized and structured plan. We basically used what little knowledge we had of the subject and common sense; we have a very simple design. Due to physics, we knew the rocket needed fins. We were debating on whether we should use 3 or 4 fins and ultimately decided on 3, which I think was the right decision because our rocket flew straight. We cut half of the smaller bottle to be placed on top, and because it was smaller, it fit snugly on the second bottle. In the compartment formed by the bottles, we rolled the egg in the padding and placed two pieces on top and bottom. We duct taped the fins to the sides of the bottle.

The Physics
Newton’s 3rd law applies to our bottle rocket. The fuel is not burned; the rocket flies from the built up air pressure and the water pushing out of its tail. That is the action force, and the rocket is forced up in the opposite direction creating the reaction force.

We made sure our rocket had 3 fins and a heavier top to make the rocket fly well and straight.

The Egg
Unfortunately, our precious egg did not survive. The best way I can describe the padding that we used it the stuff they put under the mini Christmas village scenes to look like snow. We thought that it would be a great material to use because it held the egg in place and would prevent it from breaking. Sadly, it held it too much in place. The padding was not soft enough and did not absorb much of the impact; the egg received most of it. There was nothing to increase the impact time, making the damage worse.

Results

• Distance: 63 meters
• Egg: dead
• Angle: 35 degrees
• Water: 750 mL

What went right: The distance was twice what was required and the rocket still flew well with the string wind.
What went wrong: The egg did not survive and the rocket came down faster and harder than expected.

What Did I Learn?
I learned that making a bottle rocket is not as hard as it seems. I think A.J. and I both learned to come to agreements and work together better. I also learned that the angle makes a dramatic difference in the trajectory of the rocket. The material for the protection of the egg is very important; it needs to be firm enough to protect it from the hard sides of the rocket, but soft enough to absorb some of the impact. This project helped me further understand physics in daily life. For example, the protection of the egg and the protection of people in a car is quite similar in that the egg/person cannot take all of the force from impact.