1. Building a K’nex catapult

2. History: used in war:- -Ballista's (Crossbow) -David and goliath -Cannons -Tanks -Guns

3. Basic Idea: transfer of elastic potential energy into some kind of translational/kinetic motion Where is this idea applied today: -Instruments for manufacturing -Computer Kepads/keyboards have spring technology -Hydraulic systems -Mechanical pencils or any form of a button -padlocks

4. Our idea: To follow this technology through time, specifically through propulsion -We will build a basic ballista (shoots out ping pong balls) out of K’nex -Rules to be determined

5. What did we substitute elastic potential with that is more consistent, more predictable? Chemistry!! Chemical explosions also propel things and cause similar translations to bring about the same effect. Except they are easier to control. And we don’t have to worry about breaking springs or elastic bands or even changing them for any other reason.

6. Uses of these new chemical propulsion systems: -cars (especially in the piston’s movement) -electricity generation (look at Texas for instance) -more direct uses such as fire arms and such

7. Chemical potential energy is the difference between a canon and a Ballista Here’s the basic idea of what goes on in a canon in action: http://www.instructables.com/id/Gummy-Bear- Experiment-with-molten-Potassium-chlo/