Algebra and Geometry both had work days today.

Geometry is in a weird place… Half my students know all the formulas for volumes already and the other half appear to have never have seen them before. Also, I don’t know any of the tricks to help students remember the formulas. We watched a few videos on where they come from but most are just a step away from pretty intense proofs involving limits.

I need to provide some concrete examples of where the formulas come from. Maybe fill a pyramid up with some liquid and pour it into a cube with the same base? Let me know your strategies for helping students derive volume formulas.

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Zach CoverstoneHere is a simpler version of Mr. Dardy’s comment, although his is likely more fun. This has worked well enough for me as a visual: https://www.youtube.com/watch?v=0ZACAU4SGyM

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danburfPost authorNice, thanks for sharing.

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mrdardyI have had success establishing the 1 : 3 volume ratio for cylinders and cones by using Quaker Instant Oats. I empty a canister into a big bowl, fashion a cone with the same height and have the students fill the oats canister back up. It’s goofy and fun and seems to reinforce this ratio. This, however, is only helpful if they have the idea for the volume of a cylinder under control.

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danburfPost authorThat sounds like fun, will put it away for next year. Thanks!

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