Our kids’ engineering challenge this month was to build a bridge that spanned one of the library’s delivery boxes and would support the weight of a bottle of paint. Before we started building we talked about the three major types of bridges, the truss bridge, the suspension bridge, and the beam bridge. I then reinforced the engineering process, and that re-designing and trying again are important components.
For supplies I provided pipe cleaners, popsicle sticks, string, newspapers, masking tape, straws, and scissors. Our first level of challenge was to build a bridge over the short section of the box. The second level of challenge was to build a longer bridge over the long dimension. The third challenge was to remove one of the materials they were using, so build without straws or without pipe cleaners. Only two of the children took me up on the third challenge, the rest wanted to free build and improve their existing bridges once they had passed the first two challenges. Adding extra paint bottles was a common self-imposed challenge.
If I had been building a bridge, I would have used rolled up newspapers to make a beam bridge, but no one tried that. The most popular design choice was essentially a suspension bridge, with string or pipe cleaners attached to each side of the box. This still left a lot of room for individual creation, and while there were a lot of variations on that theme, none of them were duplicates. Interestingly, as far as I can tell none of the children were influenced by the work of others. This was simply a popular design.