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### 4. Discussion

4.1 Key findings
Bridge 1 is 0.2 kg, and was able to hold a maximum of 6.8kg. The efficiently of bridge 1 is 3.4. Bridge 2 is 0.5 kg, and was able to hold a maximum of 46.8kg. The efficiency of bridge 1 is 9.36. Bridge 3 is 0.4kg, and was able to hold a maximum of 16.8kg. The efficiently of bridge 3 is 4.2. Therefore, in comparison, bridge 2 has the greatest efficiency of 9.36, as compared to bridge 1 and 3, which has an efficiency of 3.4 and 4.2 respectively. Therefore, we can conclude that the bridge 2 is better than bridge 1 and 3, and that bridge 2’s design is better than bridge 1 and 3s’ designs. Bridge 2’s design is the through truss, while bridge 1 and 3 has no design and the deck truss respectively. From this results, we can conclude that the through truss is more efficient than the deck truss and the bridge without a design (constant).

4.2 Explanation of key findings
Bridge 1 withstood the least weight as it does not have a truss or deck design to distribute the force caused by the weights evenly, causing the center of the bridge to need to withstand all the force applied by the weights and as a result, bridge 1 broke into half as the center was not able to support that amount of force applied onto the bridge by the weights. Bridge 3 was able to hold more weight than bridge 1 as it has a deck truss to distribute the force caused by the weights, which bridge 1 does not have. Therefore, bridge 3 was able to support more weight than bridge 1. Lastly, bridge 2 held the most weight as it has a through truss design, which is more effective in distributing the force caused by the weights than the deck design, allowing bridge 2 to support more weight than bridge 2. Therefore, bridge 2 was able to support the most amount of weight, followed by bridge 3 and lastly bridge 1.

4.3 Evaluation of hypothesis
Hypothesis: The bridge with the through truss design will be able to withstand the most amount of weight as compared to the other designs.

This hypothesis was proven to be correct. Our findings show that bridge 2, which uses the through truss design, had a highest efficiency rate of 9.4, as compared to bridge 1 and 3 which uses no design and the deck design respectively, that has an efficiency of 3.4 and 4.2 respectively. This proves that the bridge with the through truss design will be able to withstand the most amount of weight as compared to the other designs.

4.4 Areas for improvement
There are a few things which can be improved on.

Firstly, the sides of the bridges could have been stronger. In our tests we realised that for all the bridges other than the control, it broke at the sides rather than in the middle, so one way that we can improve our design is that we can strengthen the bridges by extending the entire design all the way to the edge and also adding more glue so as the parts of the bridge will be stuck together firmly.

Secondly, our bridge testing machine could have been more well designed. We can also use a better testing system as our metal tin was constantly swaying, which could cause our results to be inaccurate, causing our results to be wrong.

Thirdly, we also used different amount of sticks for each bridge design, so instead we used weight to test the efficiency of the design. But since each stick weighs so little, we might not be able to get a accurate reading of the bridge.

Craftsmanship was also a factor in the test as some parts of the bridge was uneven, meaning and uneven distribution of weight. In conclusion, we should use the same amount of ice-cream sticks for each bridge, build a better bridge building mechanism and improve on our craftsmanship.