Then we started testing materials for these three qualities. The materials were all household items (such as cloth, aluminum foil, clay, a rubber band and a drinking straw) that the boys had found the day before by way of a scavenger hunt.
Sometimes it was hard to decide how to rank the different materials in terms of tension, compression and torsion, but we did make a chart of the results of our testing, ranking the items from 1 (weak) to 4 (strong) in the different areas. We will use this information when we later build various structures.
If you would like to see more, go to PBS for Educators.