This is the last apple math activity for the month of September. So sad!
The measurement of circumference is hard. It is hard to imagine how big something is in general and it is really hard to imagine how big around something is. Children may be able to tell you that one apple is bigger than another, but it is really difficult for them to see more than one aspect of a problem at the same time. They are also fooled by appearances, so if you hold up one big apple that is rather skinny and another apple that is short and fat, the child cannot see both of those aspects at once. S/he will therefore choose the most obvious attribute to base her decision on which one is bigger. The child may choose the fat apple because it is fatter, or the tall apple because it is taller, but the child cannot tell you which one is actually bigger based on measurement.
In order to measure the circumference of apples, you will need several different sized apples and string.
Give each child an apple to measure and then give them each a length of string that will easily go around the middle of the apple. Have the child hold one end of the string up against the apple and then pull the string around the apple until it meets at the other side. Go around and help each child cut the string where it meets.
Once they each have their strings, you can lay them on the table top and compare the lengths of string, explaining that the length of the string is the “circumference” of the apple. They can observe their apples and their strings to come up with their own conclusions about how the measurement worked. Be sure to tell them that the longer strings represent a bigger circumference. Make sure you use all of this great math vocabulary to continue exposing children to it.