Toothpick Bridges Weren’t Built in a Day

Piles of toothpicks everywhere…glue bottles open, sketches made…now what?

This is what my 5-6th graders are beginning. we are working on sketching out what their toothpick bridges will be like, or hope to be like when they are finished in a few weeks building these models. This will be an experience they will appreciate, because they will go through various stages of frustration over the next few weeks. I know, in the end, they will have had a great time, and learned a lot about bridges.

We began today with making sketches of the bridges. We discussed the strength of both triangles and arches, and why they are used in the building of bridges, and other buildings. They students work was pretty good. Most of them really don’t draw much, and most will see that their sketches will be very different from their model. So, I told them, that as their model was becoming more and more unlike their sketch they would have to modify their sketches.

Over the next few weeks, my students will be building the toothpick bridges they will struggle with several aspects. One of the major set backs they will experience will be how to make curved lines with straight toothpicks. They will figure this out. They will go through trial and error, and with a little help from me. I want this to be more an experiment to be more of discovery than me telling students how to solve their problems.

Another area I can see my students struggling with is how to make the bridge deck and the trellis stick together. They will do some research and they will solve this problem. I will show them some models on-line, and they will also look into some books and websites for themselves to solve this.

The final issue that my students will face will be how to strengthen their bridge so that it holds the most weight. Last year I had a student build a bridge that was awesome and held a lot of weight. I believe it held something like 3 pounds of weight. Now they will try to beat that “record”. They can’t do too many trial runs with their bridge because it will weaken it. But they can see where their bridge will bend with just a little weight, and strengthen those areas.

Overall, I love this unit. These kids will be faced with several problems and they will have to solve them. i have them in 4 groups, and each group will face different problems based on their style of bridge they are building. They will all struggle at different times, and they will share their solutions with each other. That’s what I love about this kind of unit. Students will work together, and not really know they are. They will problem-solve issues, and over come those with trial and error, and  sharing of new information.

I will post a few pictures of their progress and their final project in the coming weeks.


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