Teacher2Teacher 
Q&A #6013 
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From: Joyce Jenkins <jwjboston@satx.rr.com> To: Teacher2Teacher Public Discussion Date: 2002063015:39:38 Subject: Helping students understand the need to use pi / why it works I am a Graduate student with a child entering 6th grade in TX. He was not introduced to pi in 5th grade, but I know that it will be covered in 6th grade. I am writing a unit on 6th grade geometry and would like to add one of the activities I'm using for my lesson on pi. We will measure small round objects (jar lids, etc.), as noted in the previous messages on T2T, but we will measure with strips of graph paper. Easy enough  just bend them around the circular object, and slide them across the "biggest" part of the circle, which is the diameter, of course. We record our measurement in "boxes"  counting how many little "boxes" it took to measure as out standard unit for this activity. We'll do the division and average all the answers together to get, hopefully, close to the target 3.14. But I want the students not only to understand the calculation, but why we have to use it. I will have the students pick one of the items they measured with their graph paper, place that item on a blank sheet of graph paper, and trace around it. They will then try to count how many square "boxes" are within the circle. Hard to do, but estimation is the objective. Then, since we measured in "boxes" and transferred the image to the same size "boxes" on the graph paper, the students will use their previously recorded measurement for the object and calculate the formula for area. They will then compare their physical count to the formula results, showing that pi gives a better & easier measurement than trying to count square "boxes." I am trying to provide as much handson activity in math as I can. Probably because we did not use any when I was in school (back in the dark ages). Our math classes were as interesting as licking sandpaper. Hope I've helped. Joyce Jenkins
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