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Bridge construction challenge with k'Nex

A variety of challenges, investigations, and problems can be created related to bridges. This one used K'Nex as building materials.

Bridge vocabulary

Source for these and more bridge terms.

Investigation notes

Procedure

Learners are shown photos of bridges.
Ask. Can you build a sturdy bridge with K'Nex?
Build bridges
Share constructed bridge designs
Introduce the three kinds of forces that affect the stability of bridges.
Tension - pull or stretch
Compression - push together
Torsion - twist
Tell. A simple way to test a bridge for compresion, tension, or torsion forces is to tie a piece of thread or string between two connectors that are connected with a girder and remove the girder. You can tell if the thread gets tighter, looser, or twists what kind of forces there are at different places on your bridge.
Test bridges
Share results.

Test with kilogram weight

Test with four notebooks

Test with kilogram weight

Test with kilogram weight

Statements made when testing bridges:

When the weight shifted, one side displayed tension while the opposite side showed compression.
Once we removed 2 girders, there was some slight compression at the point of removal.
When we removed two girders, force was applied which caused compression.
When we removed a smaller girder and a larger girder, force was applied which caused tension.

C. Stading, K. Flanagan, L. Haisch, K. Dusatko, S. Simpson, A. Baumann, M. Tobias, Angie Simpson, M. Foster, and C. Mettler