Circles – forever going round in the loop

Have you had the same problem as me? I teach the vocabulary and characteristics of circles, to say a 12 year old, and then perhaps two years later we have the same bright youngster and introduce the concept of π. What went wrong they couldn’t remember what the difference is between circumference, radius and diameter? We really are struggling now, forget π, they can barely remember the names yet alone what they represent. Yet year after year we repeat the same mistake. I have developed these simple steps that have helped improve my success rate.

Colour

How often do we ignore the use of colour when teaching? Not only is it more cheerful than the usual drab black and white it is a great aid to memory. Not too many colours otherwise it starts to look like an explosion at a paint factory.

Circumference

I start with the circumference. I draw it, in say blue, and now right the name underneath. But write it with a huge blue circle almost swallowing the word explaining this is how you remember it because the first letter of circumference tells you what it is.

Diameter

We now move on to the diameter. Explaining what this is I draw my blue circle again but draw the diameter vertically in red. Now I point out that the word tells you what the diameter it is just the vertical in the D. Make sure you draw the D as a capital D.

Radius

At bit of human biology never goes amiss! I tell them the bone in the forearm from the elbow to the thumb side of the hand is called the radius. When drawing a circle on the board I explain that I have to keep my elbow steady in one spot and move my arm to draw the circle. A little demonstration helps. Next I introduce Homer Simpson, remember he only has 3 fingers. I draw a circle draw the radius and with great artistic license draw Homer’s hand waving at us showing his radius bone.

These ideas are simple, silly but they really help in children remembering the names and concepts.  I continue to use the colours and remain consistent with their use. I encourage the students to do the same it aids memory and understanding.

Does anyone else have a good tip?

Has anyone tried it and had success or failure?

Make a comment and share your thoughts.