Educators' Guide: Hands-On/Mini-Activity: Arm Cantilever

Activites Index | Glossary Educator Support

Cantilever A projecting structure supported at only one end, such as a shelf bracket or diving board.

1. Place a heavy book in a bag with straps. Ask: Do you think you could support this weight with one arm? (Kids will probably say yes.)
2. Have kids first place the bag straps over their arms near the shoulder, and then over the tips of their fingers. Ask: Is it equally easy to support the weight in both places?
Illustration: comparing a load hanging near the shoulder with a load hanging from hand at end of outstretched arm.

Illustration: comparing a load hanging near the shoulder with a load hanging from hand at end of outstretched arm.

(It is much easier to support the bag close to the shoulder, near the fixed base of the cantilever, then at the unsupported fingertip end. Cantilevers support loads by bending. A cantilever can support more weight closer to its fixed end. Examples of cantilevers in structures include balconies and awnings.)

See Bridge Overview for more information.