Circumference of circles

Lesson powerpoint here.

The questions here lack a little of the meta tasks I’ve built into other stuff. But I’ve tried to build as much thinking into this as possible.

Here’s a little gallery of what you’re downloading.

Areas of circles next, I think.

I know some of these lessons are ‘prescriptive’. I don’t want people to get the wrong idea. In the lead up here I did a lesson on ‘discovering pi’. Using string to measure circumferences. The pupils found it really hard!

Measuring a circle is difficult!

We then used the ‘wisdom of the crowd’ and collated all our answers to get close to pi.

We got 3.3 ish. Eeeek.

I’m not sure if doing this helped students get a feel for pi. Measuring was so hard that students didn’t really feel like each circle they measured had the same ratio.

But I’m still glad I did it. Sometimes it’s nice to do things like measuring and to let go of student’s hands and see how they cope. Hopefully they’ll also have an appreciation for why it’s better to use the formula than measure when we come to do this lesson on circumferences.

PS : Gonna look through the links at the top and start cleaning up the sections. I’m sure there’s materials I’ve made that haven’t been listed up there.

PPS : It’s worth occasionally redownloading the PowerPoints. I often tweek and change stuff as I teach. Everything is a work in progress. Give me 20 years.

PPPS : Don Steward’s questions on this are, as always, brilliant.