Proof of Efficacy Document
The goal of this project was to produce a trebuchet or catapult to launch a clay ball as far as possible. Each group tested a certain variable multiple times to find out which one was the best. The restrictions for this project were:
After collecting data, all the groups came together to share what variable they tested and which is the best for the catapult/trebuchet so modifications could be made.
This is my CLEAR paragraph:
Out of the 4 angle degrees we tested, 0 degrees turned out to be the most effective nail angle to launch the ball. In this experiment my group and I created a miniature trebuchet made out of wood, metal, and nails. Our objective was to launch a clay ball with string while testing which angle the nail should be to achieve maximum distance. The angles we tested were 20 degrees, 45 degrees, 90 degrees, and 0 degrees. At 20 degrees the average distance the ball went was 4.68 meters. At 45 degrees the average distance was 2.88 meters. At 90 degrees the average distance the ball went was 1.10 meters. Finally the average distance the ball went at 0 degrees was 5.95 meters. As you can see in the data, the lower the angle got the more distance you can get from the ball. When we launched the ball at 90 degrees it only went an average of 1.1 meters. But when we launched the ball from 0 degrees it went an average of 5.95 meters which is almost 6 meters. The ideal angle one would want to launch from would be at a 30 degree angle. When the nail is completely flat the string should leave the nail and reach the maximum distance. The finishing nail is more reliable because unlike a regular nail which has a lip over it. The finishing nail has no lip over it letting the string slide right off without the nail catching it.
Here we made a table for the performances and data of our trebuchet:
Distance Horizontal
26.5 meters or 86.9 ft
Distance Vertical
9.6 meters or 34.5 ft
Time in Air
1.4 seconds
Velocity Horizontal
18.93 meters per second or 42.35
Velocity Vertical
6.86 meters per second or 15.35 miles per hour
Velocity Total
20.13 meters per second or 45 miles per hour
Spring Constant
89 newton meters
PE spring
6.4258 J
KEball
1.62 J
The goal of this project was to produce a trebuchet or catapult to launch a clay ball as far as possible. Each group tested a certain variable multiple times to find out which one was the best. The restrictions for this project were:
- It must have a base that sits on the ground
- Two legs that hold up an axle
- A lever arm with both a load and an effort
- It must be easily transportable and have no dimension larger than 1 meter
- You can set and release it, but not provide the firing itself.
After collecting data, all the groups came together to share what variable they tested and which is the best for the catapult/trebuchet so modifications could be made.
- A modification we made was changing the the nail angle to 0 degrees. 0 degrees turned out to be the effective because it had the highest release point which gave it maximum potential energy. At 0 degrees the average distance the projectile went was 5.95 meters.
- Our group used exactly 9 rubber bands because the group who tested the rubber band variable, said that you should put on as many rubber bands as possible. The maximum amount our trebuchet could fit without snapping was 9.
- For our arm we used a two to one ratio because it produces the farthest distance that the projectile travels. The farther the release point was from our fulcrum, the more distance there was to increase the velocity of our projectile.
- A 40 centimeter string was ideal because if your string is too small there is not enough string to be flipped. If the string is too long then it would drag on the ground before it is released causing it to not gain enough momentum. 40 centimeters (20 on each side) turned out to travel the farthest.
- We used an 8 gram ball because it has more inertia in one spot so it takes more energy for it to move so it has a lower starting velocity.
- 34 centimeters from the fulcrum turned out to be the best because a higher fulcrum creates a more vertical angle giving it more time to travel horizontally. A higher fulcrum also increase the draw distance of the rubber bands increasing spring PE. Gravity would also take a longer time pulling it down since it is higher.
This is my CLEAR paragraph:
Out of the 4 angle degrees we tested, 0 degrees turned out to be the most effective nail angle to launch the ball. In this experiment my group and I created a miniature trebuchet made out of wood, metal, and nails. Our objective was to launch a clay ball with string while testing which angle the nail should be to achieve maximum distance. The angles we tested were 20 degrees, 45 degrees, 90 degrees, and 0 degrees. At 20 degrees the average distance the ball went was 4.68 meters. At 45 degrees the average distance was 2.88 meters. At 90 degrees the average distance the ball went was 1.10 meters. Finally the average distance the ball went at 0 degrees was 5.95 meters. As you can see in the data, the lower the angle got the more distance you can get from the ball. When we launched the ball at 90 degrees it only went an average of 1.1 meters. But when we launched the ball from 0 degrees it went an average of 5.95 meters which is almost 6 meters. The ideal angle one would want to launch from would be at a 30 degree angle. When the nail is completely flat the string should leave the nail and reach the maximum distance. The finishing nail is more reliable because unlike a regular nail which has a lip over it. The finishing nail has no lip over it letting the string slide right off without the nail catching it.
Here we made a table for the performances and data of our trebuchet:
Distance Horizontal
26.5 meters or 86.9 ft
Distance Vertical
9.6 meters or 34.5 ft
Time in Air
1.4 seconds
Velocity Horizontal
18.93 meters per second or 42.35
Velocity Vertical
6.86 meters per second or 15.35 miles per hour
Velocity Total
20.13 meters per second or 45 miles per hour
Spring Constant
89 newton meters
PE spring
6.4258 J
KEball
1.62 J
Reflection
Overall this project was a lot of fun. We were allowed to choose our own groups and in my opinion we worked really well. We were mostly on the same page and if someone was off task then our group would direct whomever it was to contribute. I feel like my communication skills and my work ethic were good but I felt that I could work on my leadership skills by taking initiative when no one else is.
Another thing that went well for our group was that we found out the ideal angle for our trebuchet. We did many calculations and recorded everything we had done. After we had graphed everything we found out the ideal angle for our trebuchet was 0 degrees.
Another thing that went well for our group was that we found out the ideal angle for our trebuchet. We did many calculations and recorded everything we had done. After we had graphed everything we found out the ideal angle for our trebuchet was 0 degrees.