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Ancient Machines: Siege Engines
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Ancient Machines: Siege Engines

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Introduction to a hands-on program in building and experimenting with models of siege engines (catapults and trebuchets).

Introduction to a hands-on program in building and experimenting with models of siege engines (catapults and trebuchets).

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  • 1. Ancient Machines “The Siege Engine Edition”
  • 2. Big Idea: More than Manpower
    • Humans like the easy way out: developed technology to help construct pyramids, waterwheels, castles
    • Wedges, levers, wheels, etc all use alternate sources of power to ease the work involved.
    • Gravity and tension are today’s 2 power sources.
  • 3. Mechanical Advantage
  • 4. What Goes Up…
    • Most ancient machines were used to create, rather than destroy.
  • 5. …Gets Knocked Down
    • Forts, Castles, Walls of all shapes and sizes = Tempting Targets!
  • 6. Catapults
    • Storing Tension – lots of tension!
    • Ratchet Gears work as a winch: a piece of metal called a ‘pawl’ keeps the gears only rotating in one direction.
    • Releasing the tension on the spring arm makes it fly up until it hits the stop-bar.
    • Notice the extra construction to keep the stop-bar from snapping under the pressure.
    The ancient Romans were excellent engineers. Many of the things they built are still standing today.
  • 7. Activity: Coat Hanger Catapults Bend a coat-hanger into a catapult base, wind up a rubber band and test your flinging machine! For obvious safety reasons, we will not be throwing rocks, marbles, or anything hard.  Feel free to experiment and modify your design at home! … In which we learn that experiments with rubber bands and sponges will hurt less than the alternative.
  • 8. Trebuchets
    • A trebuchet works with a lever and counterweight, using gravity (potential energy transformed to kinetic) to fling the projectile.
    • Range and accuracy can be altered by changing the length of the swinging arm, the mass of the ball, the mass of the counterweight, and several other factors.
  • 9. Success or Splat?
    • Be a siege engineer!
    • NOVA: Destroy the Castle http://www.pbs.org/wgbh/nova/lostempires/trebuchet/destroywave.html
    • GlobalSpec: Treb Challenge http:// www.globalspec.com /Trebuchet/
  • 10. Activity: Testing Trebuchet Range
    • Try out our working tabletop trebuchet! Try for distance or for one of the targets.
    • Remember not to fire AT anyone, and stay out of the firing line while waiting your turn.
    • Please remember to recover your “ammunition” after each firing!
    The “Little Dragon” Trebuchet was the model for our version.
  • 11. Projectile People—Possible?
    • Also known as: my favorite movie stunt

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