Aim: The purpose of this experiment was to test our knowledge on physics, forces, pressure, and calculation.
Equipment: All the main equipment needed is a soda bottle, a launch station, stopwatch, 30m tape measure, air pump, rubber cork, and water. Though, you are able to add other materials to decorate or improve your rocket aesthetics and functionality. For my team’s rocket, we used cardboard, hot glue, coloured paper, and a marker.
Method:
- Empty out a soda bottle.
- Decorate or enhance the bottle by using any material of your choice.
- Fill up 1/3 of your rocket with water.
- Go outside.
- Set up the launch station.
- Lay out the 30m tape measure.
- Use a cork with a hole so you can pump pressure into the bottle.
- After a few pumps, watch out for flying plastic rockets.
Results: Include distance/ time recordings, your speed calculation, and picture.
| Distance travelled (m) | Time taken (s) | Speed calculation (ms-1) |
| 9.9m | 2.22, 2.0, 1.81, 1.42, 1.25, 2.321.86s (average) | 5.32ms-1 |
Discussion:
- What are the forces acting on your bottle rocket?
- Are they balanced/ unbalanced?
- What is net force and how does this relate to the forces acting on your bottle rocket?
- What are the strength of forces acting on it at different stages?
- How do the forces acting on the bottle rocket affect the motion of the bottle rocket at different points?
- Why do you think results may vary in the class?
There are 4 forces acting on the bottle rocket. The 4 being thrust, weight, air resistance, and pressure. The forces were unbalanced. Because it is unbalanced, all the forces are different numbers, in which the speed won’t be zero. Net forces varies from balanced and unbalanced forces, as it is the sum of all forces acting upon the object. But since we don’t know the amount of each force there are, we aren’t able to find the actual net force. There are however, the strength of forces acting in different stages. During the pumping, the pressure was increasing more until we eventually had to let go to let it launch. As it launches, the weight of the water decreases because the pressure was released, causing the water to thrust the bottle into the air. Due to the help of the improvements made on the bottle, the triangle shaped cardboard and the bottle being streamline shaped, the air resistance increased greatly. All of those forces have affected the motion of the bottle at different points; from the pumping, to the launching, and to the flying. Everyone in the class has different results as we all have various shapes, sizes, weights, and refinements.
Conclusion:
- How was your bottle rocket successful/unsuccessful and why (relate your answer to physics ideas)?
- How could you improve it?