Catapult Project by William Armstrong https://padlet.com/533140/4oe5szlw6g9d Will Armstrong and Juan Cruz en-us 2018-11-02 00:26:45 UTC 2026-01-03 11:48:28 UTC hello@padlet.com Materials used, 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299633133 - Popsicle sticks - 18 
- Rubber bands - 1 
- Cardboard - 2 by 4.5 inch slab (The cardboard was the base so 5 by 11.5 Centimeters were the dimensions of our base)
- Yarn - 17 inches 
- Tape - 14 inches 
- Clothespin - 1 
- Dixie cup - 1 
- Glue - 1 bottle of Gorilla Glue -  Cotton ball - 1

Total nine items, all of which serve a purpose. ]]> 2018-11-02 00:29:21 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299633133 Objectives, 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299634808 1)         Create a catapult that will toss a projectile onto a target (a small cup) 3 m away using only the supplies provided on the supply list.
2)         Determine the initial velocity of the projectile based on measurements.
3)         Conduct research of catapults to help refine brainstorm design.

]]> 2018-11-02 00:37:56 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299634808 Guidelines, 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299635799 1. Catapult was 20 by 19 centimeters, and the height was 14 centimeters. 
2. Catapult never took longer than 15 seconds to fix/launch.  3. Catapult was powered by the releasing of the arm and snapping forward. 
4. The trigger was a clothespin that when released, set the arm in motion. 
5. All repairs were done in under one minute 

]]> 2018-11-02 00:43:50 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299635799 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299638324 - The catapult was 2/3 in terms of hitting the distance of the cup. The one miss was shy of the cup by about half a foot, if that. 
- The build held up well, i never had to fix it. I also dropped it a couple of times but there was no damage. 

]]> 2018-11-02 00:57:39 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299638324 Front View 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299660106 2018-11-02 03:12:29 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299660106 Side View 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299660263 2018-11-02 03:13:40 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299660263 Launch 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299660314 2018-11-02 03:14:20 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299660314 Parts and Dimensions 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299660431 The Dimensions of the catapult are 20 by 19 centimeters, and the height was 14 centimeters. 
- The stack of Popsicle sticks served as a surface for the Popsicle stick doing the launching to bend back on and launch. 
- The half Dixie cup housed the cotton ball. 
- The rubber band held the arm of the catapult to the Popsicle stick it used as an anchor. 
- The clothespin was glued to the bottom of the cardboard, and served as the release for the arm. ]]> 2018-11-02 03:15:42 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299660431 Parts and Dimensions Pt. 2 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299660720 - The string held the Popsicle stick (the stick used to hold the arm in place before release) underneath the stack in place. 
- The Tape held one side of the stack of Popsicle sticks in place. 
- Cardboard served as a base so the catapult wasn't off balance. 
- Glue held everything tape and rubber bands didn't in place. 
- Cotton ball is pretty self explanatory. ]]> 2018-11-02 03:18:51 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299660720 3 Types of Catapults 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299873707
  • Trebuchet - The Trebuchet, first originating in China in the 4th century, uses manpower to swing an arm that hurls a projectile. Trebuchets are big, they’re typically 100 ft tall, sometimes larger, and are primarily made with wood and sometimes reinforced with metal. The arm of the trebuchet is attached to an axis like structure in the middle of the trebuchet, and a weight sits on the side nearly opposite the arm. There’s a sling on the end of the arm for the object.  The weight is hoisted up, and when it’s released it swings down and swings the arm around, throwing the projectile. Typically the weights are pulled up by men, and released, so trebuchets are still pretty labor intensive, and not mechanized. 
  • Ballista - A ballista is a crossbow like catapult used to shoot projectiles rather than throw them. The ballista was first used in early Greece, and is essentially a larger and more elaborate play on a crossbow. Ballistas fire by pulling back a wire attached to a curved shaped board at the nose. When the wire is released, the projectile fires.  The heavier the projectile, the more tension needed to fire the projectile the same distance as a lighter object. Ballista typically weigh somewhere around 500 pounds, but that’s more of a shot in the dark, ballistas can weigh anywhere from too heavy to carry to a couple tons. Ballista at their strongest can shoot 200 pounds of weight, and even smaller batista's can shoot 55 pounds of weight. 
  • The mangonel, the catapult everyone knows, originated in China around the same time as the trebuchet. The mangonel, similar to the ballista, used tension to fire projectiles. The thought was someone would pull an arm back, further than it wanted to go, and build up tension in the catapult. The Projectile would sit in a basket or sling at the end of the arm. Than the arm would be released by a number of different means, and the arm would hit a beam and stop the motion and the projectile would be thrown. The mangonel can be big, much bigger than a person, or small like we did. Mangonels were most commonly used in sieges for knocking down walls and doors. 

    • ]]>     2018-11-02 16:20:48 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299873707     Trigger to launch, and sources of error 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299874376
  • The bottom half of the clothespin was glued to the popsicle stick used to hold the arm. When the arm was pulled back, the clothespin would hold it in place. When the catapult was ready to fire, you’d move the clothespin to the right, you wouldn’t raise the top part, you’d move it so the popsicle stick would jolt up, releasing the tension. When the clothespin was released, the arm of the catapult would fling forward and stop at about a 90 degree angle with the popsicle stick on the bottom, right by the rubber band, and it would rebound back to its starting position. Than you could pull it back, clip it under the clothespin, and do it again. 
  • Our release was shaky, so the catapult moved when it was fired, so the projectile was always off center. We could have had a better trigger and release for a straighter shot. We could have has a more consistent shot. Our catapult was only constant distance wise half of the time. We almost always made the 9 meters, but on occasion the catapult would over or under shoot and we'd flatout miss the cup. We could have added a bar for the arm to hit when the catapult fired to have more accurate and consistent distances. Finally it would have been easier to have a better release. Ours was fine, but it would have been easier to have something like a pin you pull out and the catapult fires rather than manually unhooking a clothespin. 

    • ]]>     2018-11-02 16:22:03 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299874376     Calculations 533140 https://padlet.com/533140/4oe5szlw6g9d/wish/299874602 - Horizontal component of the projectile’s velocity - 2.27 m/s 
    - Time to reach maximum altitude - 0.74 seconds
    - Maximum altitude of the projectile - 3.2 feet
    - Initial vertical velocity - 7.4 m/s
    - Initial resultant velocity - 7.75 m/s

    ]]>     2018-11-02 16:22:30 UTC https://padlet.com/533140/4oe5szlw6g9d/wish/299874602