4. Discussion

Through discussion, we realized that we needed more data to make it a more reliable test. There could have been other factors affecting our experiment such as wind. Therefore we took three experiments and did an average of the distance travelled for each amount of weights based on the data we collected. Also, there was another extra investigation that our science teacher, Mr Low gave us. It involved putting as many weights as we could into the counter-weight box so see how far the trebuchet could throw the eraser or how much weights the counter-weight box could take before breaking.

4.1 Key findings

We found that the projectile cannot be released if there are less than two ankle weights. Also, there was a part of the experiment 2 where at 7 weights (Third Try) the eraser flew directly up. This might have been caused by human error and the way of releasing the eraser.

4.2 Explanation of key findings

The counterweight was too light. The projectile could not be released over the starting point and kept landing backwards. There was not enough gravitational force in the counter-weight box to power the trebuchet thus we deemed it as negligible.

4.3 Evaluation of hypothesis

From this results, we can say that we have proved our hypothesis which is, the higher amount of ankle weights added, the further the projectile will travel. It is true that the more amount of weights we put into the counter-weight box, the distance travelled by the easier is much larger. This is because the more weights we put into the counter-weight box, the more amount of gravitational force is present and therefore there is more kinetic energy when the arm swings so the eraser can move further and faster.

4.4 Areas for improvement

1) We could have started our project earlier as there were some time management problems in the start as we were scrambling to find some materials to use for the trebuchet and we also had not much time in cutting the wood.

2) We could have also used a specialised trigger block just to release the eraser. This is because there were some human errors in the experiments and the results could have been unreliable.

3) Using the measuring tape to measure the distance travelled would have improved the experiment, as we estimated where the eraser landed and calculated not very accurately.