Science Fair ProjectProjectile Projection

Trebuchets

Jack Tiffany

Statement of the Problem

Does the weight of the counterweight and/or projectile affect the distance the projectile is launched?

Project Overview

I shot the projectiles while changing the weight of the projectile and that of the

counterweight. I then recorded all of it on a chart.

Research Summarize your research here in three to five bullet points:

Trebuchets have been used since the middle ages. Trebuchets are more accurate than catapults.

Trebuchets are more simple to make. The Trebuchet was invented in China in 300AD

Variables

Independent variable: The weight of the counterweight and the projectile. Dependent variable: The distance the projectile is launched.

Constant variables: Length of the arm, size of trebuchet, distance arm is pulled, amount of time launched, size of basket.

Control group: The 10 launches with my 1lb weight

Hypothesis Hypothesis/Prediction is the more the weight of the counterweight the

farther the projectile will go. The heavier the projectile the less far it will go.

Materials Trebuchet from Science Olympiads 20g, 40g, and 60g ball from Science Olympiads 3 meter sticks A 1lb, a 2lb, a 3lb counterweight

Procedure

1. set the counterweight to 1lb 2. Load the 40g ball into the basket 3. Pull back string to mark 5. 4. Launch, measure, and record. 5. Repeat steps 2-4 9 more times 6. Set the counterweight to 2lbs. 7. Repeat steps 2-4 10 times. 8. Set the counterweight to 3lbs 9. Repeat steps 2-4 10 times 10. Record all the results on the chart

Data/Observations (Analyzes)

1 kg at 40 grams 2kg at 40 gramms rams 3 kg at 40 grams

trails distance trails distance trails distance

1 1.24 1 1.42 1 1.622 1.29 2 1.34 2 1.72

3 1.27 3 1.3 3 1.8

4 1.28 4 1.4 4 1.61

5 1.46 5 1.45 5 1.63

6 1.29 6 1.4 6 1.6

7 1.26 7 1.38 7 1.64

8 1.34 8 1.4 8 1.7

9 1.23 9 1.27 9 1.8

10 1 10 1.43 10 1.5

1.266 1.379 1.662

Conclusion

The heavier the counterweight, the farther the projectile is launched. The heavier the projectile is, the less distance the projectile is launched.

Possible Experimental Errors

I may have launched it at mark 4 a few times. The string may have caught on the arm, reducing the distance. I may have not accurately measured the ball a few times.

Applications and Recommendations

To improve the results, I would have run the experiment 15 times instead of 10. Also I would have made sure to check the recoil. This could be used in real life if you were trying to throw a basket ball and a bowling ball. You wanted to throw them to a friend and didn’t

know how much force to use.