1. Jessica Linus Ms. Fitzpatrick December 5,2012

2. Define The Problem Students will research, design and construct a catapult that will be able to launch a clay ball of varying sizes (3 grams, 4 grams, 5 grams) a certain distance.

3. Brainstorming The catapult must be stable and the projecting arm must limit restriction to enable it to be elastic enough to hurl the clay bar a certain distance. Rubber bands should be efficient enough to launch the projecting arm.

4. Research A catapult is a device used to throw or hurl a projectile a great distance without the aid of explosive devices— particularly various types of ancient and medieval siege engines. Although the catapult has been used since ancient times, it has proven to be one of the most effective mechanisms during warfare.

5. Identify Criteria and Constraints Criteria: (1)Students will supply all materials for this project (2) Students will not be allowed to purchase kits (3)This is an individual assignment (4) Students must use the 12-Steps of the Engineering Design Process to complete this assignment (5) Students must document each step in a presentation format using any presentation software (PowerPoint, Prezi, etc) Constraints: (1)Elasticity (2)Budget (3)Probability of projection (4)Stability

6. Explore Possibilities

7. Making A Model

8. Testing Three-gram clay ballFour-gram clay ballFive gram clay ball Test 1 time (seconds).54.68.53 Test 1 Distance (cm)150200130 Test 2 (seconds).62.54.58 Test 2 Distance (cm)120100 Test 3 Time (seconds).71.38.50 Test 3 Distance (cm)13070140 Test 1 speed (cm/s)277.8 cm/s294.1 cm/s245.3 cm/s Test 2 speed (cm/s)193.5 cm/s185.2 cm/s172.4 cm/s Test 3 speed (cm/s)218.1 cm/s221.2 cm/s232.6 cm/s

9. Refining I would have used a lighter wood, instead of a 2x4 perhaps a 2x2. I would make the projecting arm longer, instead of 12 inches, perhaps 14 or even 16” I would Make the sides longer, instead of 12” probably 18”. I would also make the structure before the projecting arm stable using nails instead of screws.

10. Creating To create my catapult I used: 3 pieces of wood 12 inches long 8 pieces of wood 6 inches An assortment of small screws and/or nails 1 large rubber band or several smaller ones 2 eye hooks (to the right of the rubber band Some glue (optional but a good idea)

11. Results My catapult was efficient, however due to lack of stability it wasn’t able to fling items far distances.