C

This lesson was about civil engineering and bridge-building. We introduced the kids to what civil engineers design and talked a little bit about forces and gravity. We hinted that triangles are typically used in sturdy structures. The activity for the day was to build a bridge using toothpicks and gumdrops that could span 10". Each group had to draw out their design on paper before they were given any materials. When they were done building, they tested their bridges by adding pennies to a cup suspended from the bridge. There turned out to be a bit of a shortage of toothpicks. On average, about 30 gumdrops and 50-60 toothpicks were used by each group. The strongest bridge held almost 50 pennies, so we had that group talk about their design. The gumdrops were a little messier than anticipated so it would be a good idea to lay out newspaper on the desks next time.