Catapults and Trebuchets

Student Journal

AFTER SCHOOL STEM ACADEMY

CatapultsandTrebuchets

WABSAFTERSCHOOLSTEMACADEMYSpring2017

OVERVIEWOver the course of the first three sessions, you will build small-scale catapults and test them based on various criteria. Then, you will design and build a larger trebuchet, explore concepts of load and balance point. In the final lesson, you will test your designs across all three criteria – accuracy, power, and knocking down a tower.

Lesson 1 – What is a Catapult? Lesson 2 – Go the Distance: Testing Power Lesson 3 – Right on Target: Testing for Accuracy Lesson 4 – Assembling a Trebuchet Lesson 5 – Finding the Best Load Lesson 6 – Trebuchet Olympics

CATAPULTVS.TREBUCHETA catapult is any device that throws an object, although it commonly refers to the medieval weapon. Trebuchets are a type of catapult, using gravity (with a counterweight) or traction (people pulling down), to propel the arm and often employing a sling at the end of the arm for greater distance.

VOCABULARY

Accuracy: The ability to hit the target.

Catapult: A machine that launches a projectile.

Projectile: An object that is launched or thrown, usually in the air, by a force.

Quadrilateral: A polygon with four sides. Examples include squares, rectangles, and trapezoids.

Triangle: A polygon with three sides.

Torque: A twisting force that tends to cause rotation.

Force: The push or pull on an object.

Fulcrum: The support about which a lever pivots.

Load: A weight or source of pressure.

1

Lesson One What is a Catapult?

TODAY’SCHALLENGEYour challenge today will be to use some everyday materials to create catapults that can launch ping-pong balls. The catapult you design must be able to knock down a tower made of plastic cups.

BUILDINGMATERIALCHOICES• Cardboard• Masking tape• Plastic spoon• Rubber bands• Craft sticks• Straws• Ping-pong ball

MYMATERIALSLIST

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Lesson One What is a Catapult?

DESIGN

Sketch your design for your catapult below:

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Lesson One What is a Catapult?

TESTRESULTS

NUMBEROFCUPSKNOCKEDDOWN

ATTEMPT1

ATTEMPT2

ATTEMPT3

ATTEMPT4

ATTEMPT5

NOTES:

NUMBEROFCUPSKNOCKEDDOWN

ATTEMPT1

ATTEMPT2

ATTEMPT3

ATTEMPT4

ATTEMPT5

NOTES:

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Lesson One What is a Catapult?

REFLECTION

1. What worked well in your catapult design?

2. What aspects did you have to modify?

3. Were you able to knock down the cup tower? How many times?

4. What would you do differently next time?

5

Lesson Two Go the Distance: Testing Power

TODAY’SCHALLENGE

Build a catapult that can launch a mini-marshmallow the longest distance.

BUILDINGMATERIALCHOICES• Cardboard

• Masking tape

• Plastic spoon

• Rubber bands

• Craft sticks

• Straws

• Paper bowls

• Plastic lids

• Small paper cups

MYMATERIALSLIST

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Lesson Two Go the Distance: Testing Power

DESIGN Sketch your design for your catapult below:

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Lesson Two Go the Distance: Testing Power

TESTRESULTS

DISTANCEMARSHMALLOWTRAVELED

ATTEMPT1

ATTEMPT2

ATTEMPT3

NOTES:

DISTANCEMARSHMALLOWTRAVELED

ATTEMPT1

ATTEMPT2

ATTEMPT3

NOTES:

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Lesson Two Go the Distance: Testing Power

REFLECTION

1. What worked well in your catapult design?

2. What aspects did you have to modify?

3. How far was each team able to launch a mini-marshmallow?

4. What do you think helped launch the marshmallow farther?

9

Lesson Three Right on Target: Testing for Accuracy

TODAY’SCHALLENGE

Build a catapult that can launch a cotton ball accurately. In this activity, accuracy is the ability to get the cotton ball into the bowl.

BUILDINGMATERIALCHOICES• Cardboard

• Masking tape

• Plastic spoon

• Rubber bands

• Craft sticks

• Straws

• Paper bowls

• Plastic lids

• Small paper cups

• Cotton ball (for testing)

MYMATERIALSLIST __________________________

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Lesson Three Right on Target: Testing for Accuracy

DESIGN Sketch your design for your catapult below:

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Lesson Three Right on Target: Testing for Accuracy

TESTRESULTS

NUMBEROFCOTTONBALLSINBOWL

ATTEMPT1

ATTEMPT2

ATTEMPT3

ATTEMPT4

ATTEMPT5

NOTES:

NUMBEROFCOTTONBALLSINBOWL

ATTEMPT1

ATTEMPT2

ATTEMPT3

ATTEMPT4

ATTEMPT5

NOTES:

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Lesson Three Right on Target: Testing for Accuracy

REFLECTION

1. What worked well in your catapult design?

2. What aspects did you have to modify?

3. How accurate was the catapult that your team designed?

4. What would you do differently next time?

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Lesson Four Assembling a Trebuchet

TODAY’SCHALLENGE

Build a trebuchet and make it work.

BUILDINGMATERIALCHOICES• Empty water bottles

• Rulers

• Ruler

• Wooden dowels (20-inch)

• Wooden dowels (4-inch)

• Paper cup (6-9oz)

• Washers

• Rubber bands

• Binder clips

• Masking tape

• Paper bowls

• Paper

MYMATERIALSLIST __________________________

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Lesson Four Assembling a Trebuchet

DESIGN Sketch your design for your catapult below:

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Lesson Four Assembling a Trebuchet

REFLECTION

1. What worked well in your catapult design?

2. What aspects did you have to modify?

3. How accurate was the catapult that your team designed?

4. What would you do differently next time?

16

Lesson Five Finding the Best Load

TODAY’SCHALLENGE

Find the best amount of load (number of washers) to shoot the cannonball the farthest.

BUILDINGMATERIALCHOICES

• Trebuchets from Lesson Four

• Additional washers

• 4-inch dowels

• Rubber bands

• Binder clips

MYMATERIALSLIST __________________________

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Lesson Five Finding the Best Load

DESIGN Sketch your design for your catapult below:

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Lesson Five Finding the Best Load

REFLECTION

1. What worked well in your catapult design?

2. What aspects did you have to modify?

3. How accurate was the catapult that your team designed?

4. What would you do differently next time?

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Lesson Six Trebuchet Olympics

TODAY’SCHALLENGE

Use your trebuchet to compete three tests – accuracy, power, and ability to knock down a tower.

BUILDINGMATERIALCHOICES• Trebuchets from Lesson Five

• Cotton balls

• Paper bowl

• Ping-pong ball

• Plastic cups

• Masking tape

• Mini-marshmallows

• Measuring tape

• Olympic Passport (one per group for recording results)

MYMATERIALSLIST __________________________

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Lesson Six Trebuchet Olympics

DESIGN Sketch your design for your catapult below:

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Lesson Six Trebuchet Olympics

REFLECTION

1. What worked well in your catapult design?

2. What aspects did you have to modify?

3. How accurate was the catapult that your team designed?

4. What would you do differently next time?

22