Here is a Circular GEOBOARD (hands-on math tool) that can be used with kids for FUN Measurement lessons as well as geometry and other areas of math.
|Circumference and Diameter with an elastic and hair bands|
The above picture shows how kids can use the Circular Geoboard for finding the Diameter and the Circumference of a circle. It could also show symmetry, fractions, etc.
|Circumference and Chords|
You can purchase geoboards or make your own. Some geoboards are double sided (a square on one side and a circle on the back).
The Geoboard that you see above was inspired by my trip to the Dollar Tree. (I go often! I'm kind of obsessed!!! It's in the same mall as Michaels' Craft store and Marshalls.) I found this great package of 5 Wipe-Off 12 Pin Circular Boards.
I asked my husband for a spare scrap piece of wood. He cut a square for me and sanded the wood. Then I glued one of the circular Wipe-off Boards to the wood and hammered push pins into the 12 dots that formed the circle. Voila, an inexpensive hands-on manipulative. You could add a push pin to the middle to demonstrate Radius.
If you wanted to make a board but can't find the Wipe-off Boards, you could use a compass and protractor to sketch a circle right on a piece of wood. I'll provide links in case you'd rather check out the store-bought versions of geoboards. :)
Have fun with math!