The goal of this project was to create a launching device to fire a projectile as far as possible within certain restrictions including the following.
- A base that sits on the ground
- 2 legs that hold up an axle
- A lever arm with a load and effort end
- Device must be easily portable by one person
- All dimensions within 1 meter
- Outside forces may “set” but not “fire” the device
During this project, we chose one variable to change for this experiment and our group picked axle height. In this experiment, we tested multiple heights of the axle on our trebuchet and collected distances from each trial.
We collected data from 3 heights that produced the following data.
Axle Height(m) |
0.26 |
0.23 |
0.19 |
Distance(m) |
2 |
1 2/3 |
1 1/3 |
This leads me to observe that about every 4 cm we raised the fulcrum it increased the distance traveled by ⅓ m. With this observation, I can conclude that a higher axle height increases the distance traveled.
We also collected data from 2 additional heights.
We also collected data from 2 additional heights.
Axle Height(m) |
0.305 |
0.34 |
Distance(m) |
2 2/3 |
3 |
Independently, these numbers appear to follow the same ⅓ m per 4 cm growth, but when combined with previous data, a jump appears. This may be due to human error when collecting data or it may be due to the changing our stopping bar into a thicker one. This most likely changed the angle of launch therefore changing the horizontal.
Our prototype design included a stopping bar and basket but we ended up making many changes to our design, noted in the following.
Our prototype design included a stopping bar and basket but we ended up making many changes to our design, noted in the following.
- Added another rubber band to increase PE to increase distance
- Removed the stopping bar as at this scale it is more of a hindrance than a help
- Replaced the basket with nail bent backwards 10° for a more optimal release angle for this situation
- We changed our projectile be 10 grams
Distancehoriz |
30 meters |
Distancevert |
6.3 meters |
Timein air |
1.17 seconds |
Velocityhoriz |
26 meters/second |
Velocityvert |
10 meters/second |
Velocitytotal |
28 meters/second |
PE |
3.9 Joules |
KE |
10.6 Joules |
Spring Constant(K) |
133 Newtons/meters |
Release Angle |
28° |
Overall, this project went fairly well. One thing I did well was reduce disharmony among my group. My group was composed of only "leader" type people so harmony was hard to come by. I was able to find compromises between good ideas and cull bad ones. I gained a skill of data collection as well. Towards the end of the project, we had to quickly collect data which helped me gain this skill.
There were also some bad parts in this project as well. One way that this project could have gone better was I could have been at school to work on the catapult for longer. During the middle of the project, became sick and was unable to complete a much work as I would've preferred. I will improve this by keeping better track of my less. Another thing that I could've done better was I could have not been as stuck as firmly with some of my ideas. During the project, sometimes two opposing would be produced and I would sometimes be hard to sway to the other side. I will continue try to improve this issue by being more open minded to other ideas.
There were also some bad parts in this project as well. One way that this project could have gone better was I could have been at school to work on the catapult for longer. During the middle of the project, became sick and was unable to complete a much work as I would've preferred. I will improve this by keeping better track of my less. Another thing that I could've done better was I could have not been as stuck as firmly with some of my ideas. During the project, sometimes two opposing would be produced and I would sometimes be hard to sway to the other side. I will continue try to improve this issue by being more open minded to other ideas.