Educators' Guide: Hands-On/Mini-Activity: Toothpick Truss

Activites Index | Glossary Educator Support

Truss A skeleton-like structure composed of struts (short straight pieces), some in compression and some in tension, joined to form a series of triangles.

1. Have kids construct a rectangular box as shown here by joining toothpicks with small white beans or navy beans, soaked overnight before the activity, or gumdrops. Have them test its stability by pressing down on it and wiggling it.
Illustration: structure built as square shapes with toothpicks and gumdrops.

Illustration: structure built as square shapes with toothpicks and gumdrops.

2. Now challenge kids to add more materials to strengthen the box. (Kids will probably find that they can stabilize the box by adding cross-pieces and triangular braces, as in the example shown here.)
Illustration: Structure with cross braces added, making triangular shapes, with toothpicks and gumdrops.

Illustration: Structure with cross braces added, making triangular shapes, with toothpicks and gumdrops.

3. Have kids extend their trusses and see how wide a gap they can cross.

Video Connection "Trusses" from Bridges (see Program Descriptions)

Try the Loads Lab.

Photo: Scotland's Firth of Forth Bridge.

Photo: Scotland's Firth of Forth Bridge.

Scotland's dramatic Firth of Forth Bridge gets its strength from cantilevers and trusses. The video segment "Trusses" from Bridges explains how it works. (See the Program Description to locate the segment.)