Secrets of Lost Empires II—Medieval Siege

Student Handout

Fling It!

King Edward has asked you to design and build a mighty siege machine—called a trebuchet—that will fling a grape across a far distance. You have been provided with some materials to build your trebuchet: You must use plastic soda straws for all long construction pieces and a straightened paper clip for the axle. Your missile will be a grape. Study the diagram below before designing your grape-throwing trebuchet.

You will need to construct the following parts of a working trebuchet:

  • two triangular pieces for the sides of the frame; these will need to be supported or braced to stay upright

  • A long, strong throwing arm pierced by the axle; the short end of the throwing arm should have a small, heavy counterweight that will allow the throwing arm to swing freely without touching the sides of the frame or the ground

  • A sling that will hold the grape during the upswing and release it at the top of the arc

To connect the straws together, pinch the end of one straw and slide it into the end of another straw. Wrap a band of tape around the joint to secure the connection.

Consider these and other methods as you design and build your trebuchet. As you work, keep a journal describing your design successes and failures. Include detailed, labeled drawings and descriptions in your journal. Tell what you discovered as you worked.

Diagram of trebuchet model