Energy Converter Building Project

You will build a device that employs the concept of conservation of energy. Your device will convert energy from one form to another in order to achieve a simple goal. You may work alone or in a group, groups may not exceed four members.
Possible Devices
  • Mouse-Trap Racecar (Elastic Potential > Kinetic)
  • Catapult (Elastic Potential > Kinetic)
  • Trebuchet (Gravitational Potential > Kinetic)

Materials: All materials must be school appropriate. You are responsible for procuring any materials that you may need. The projectile launchers should be designed to launch 3/8" dia. spheres (approx.). You may use mousetraps but not rat traps. You may use plans found on the Internet but you may not purchase a pre-fabricated kit. No dimension of the device may exceed one meter (remember you may have to take this on the school bus).

Written Portion: Along with your device you must submit a written explanation of its workings. Your group will collaborate and turn in one typed essay. See Part II of alternate assignment for details. The complete project is approximately equal to one test grade, this includes the written portion (10pts) and the device (50pts).

Behavior: Any complaints/issues throughout the school or in other classes that arise from this project will earn you an automatic zero plus a disciplinary referral, example; your mousetrap "accidently" winds up on a teacher's chair. If you are arrested for shooting marbles through a neighbors window with your catapult I will treat that the same as an in-school issue.

Timeline
This project will use two class periods of time.
Day One (4/12/12) - half period early on in project for you to ask questions, make plans with partner(s).
Day Two (4/23/12)- half period late in project for you to ask questions, test or trouble-shoot device. Point of no return - after this date you may not change projects.
Day Three (Weather permitting 5/4/12)- full period, similar devices will compete, everyone will see all of the other devices, good times will be had by all.

Device Points (4 Categories / 50 Points)


1) Function (25 Points)
  • Does Not Move/Operate (5-8)
  • Works but not properly (15-18)
  • Works well (20-23)
  • Works Perfectly (25)

2) Performance (10 Points)
  • Does not Move/Operate (2)
  • Non-competitive (4)
  • Below Average (6)
  • Average (8)
  • Above Average (9)
  • Best (12)

3) Quality (10 Points)
  • Poor craftsmanship (4)
  • Properly built (8)
  • Well built (9)
  • Exemplary (12)

4) Appearance/Style (5 Points)
  • Poo (2)
  • Meh (3)
  • Aiight (4)
  • Day-Umm (5)



Alternate Assignment

You may choose to not build a device for your project. In that case there is an alternate assignment that could earn you the same grade. Alternate assignments are to be completed individually.

Part I. General Research
List and explain the function of four different siege engines.

Part II. Specific Research
Pick one siege engine and write up a thorough explanation of its functionality. Your explanation must address the following concepts (and use the terms).
1. Projectile motion
2. Horizontal and vertical velocities
3. Forces
4. Potential, Kinetic, and Conservation of Energy
5. Work, Power, and Simple Machines

Part III. Calculations
Regardless of your choice of siege engine, use the given information to perform the calculations.
Given:
  • Your army is located 200m from the enemy castle walls.
  • You will be firing projectiles that are 113kg (250lbs)
  • You need to have your projectile in the air for 25.0s.
  • Ignore friction/air resistance/wind/birds or any other outside influences.
Calculate:
  • Muzzle velocity (speed and angle).
  • Maximum height.
  • Height on impact.
  • Velocity on impact.