62 toothpicks

This is the third post, in what’s become a bit of a series, on some of the things I’m doing with my summer school students. In the last post, I wrote a little about authentic assessment. Here is an example of one from my summer math class.

You’d be surprised at just how much weight a single toothpick can hold. We zeroed in on the exact number during a math lab last week. Students have been working on adding/subtracting/multiplying/dividing fractions, so we got out the balances and started weighing things down to fractions of a gram. The students loaded the items (rocks, quarters, lead weights) into a cup on a pair of toothpicks and kept a running tally of the weight. After a while, the cup filled up and the students ran out of items light enough to weigh on the balances.


At this point I brought out some bigger weights and we started stacking them on the toothpicks. When the toothpicks started bending we added 100 gram weights, then 50 gram weights, and so forth until it finally broke. It was hilarious to watch the students ooh and ahh everytime they added another weight. When it was all done, the students added up all the numbers and did some division to figure out how many toothpicks it would take to hold me up. The answer – 62 toothpicks.


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