They know, they really know!


book coverA few years ago, one of our reformer curriculum guides bought the book “A Bridge to Algebra 2.” This is a book for students who did not “get” Algebra 1, in a state that was about to, or just had, implemented a required Algebra 2 credit for graduation. It’s got a lot of applications, and is heavily into applied math.

One of what I considered to be the easiest (most accessible to students) experiments was to use large graduated cylinderPlastic_graduated_cylinder-1000mls, and add in film canisters weighted with pennies.

When we first got these books, I was overjoyed. I was so excited to do hands-on. It was so resisted by everyone else (mostly because the district provided no supplies) that it died an early death – only one year of the trial, and the books were retired. I bought 6 graduated cylinders. I collected film canisters. I had kids work this – measure the volume of the water as you plop in a cylinder, what could make more sense? the slope of the line gives you the size of a cylinder.

What did we get? The slope of the line is the number of pennies in the cylinder. The number of pennies is the most important thing. Nobody, nobody at all, could come up with the increase in volume being due to the volume of the film canister. I was stunned.

Fast forward 4? 5? years. The state requires Algebra 2 . The state is switching 9th graders to CCSS and assessment in 2014/15. A bunch of us joined a 4 year long study to improve science teaching for 8th graders (I sneaked in). I have a non-class math class. I want projects. I use this as a project.

Almost every kid gets that the cylinder provides the volume. Almost every kid gets that the number of pennies is unimportant (as long as the cylinder sinks) – and if they don’t, they’re willing to experiment to prove it to themselves. Everyone gets that the y-intercept is the amount of water we started with, that the amount of water does not go up, but the level does.

OMG maybe we can go back to the hands-on fun book. I am sooo happy!!

Whoops, better blame being ahead of our time in doing hands-on work.


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