According to the Pi Day website

Pi (π) is the ratio of a circle’s circumference to its diameter. Pi is a constant number, meaning that for all circles of any size, Pi will be the same.

The diameter of a circle is the distance from edge to edge, measuring straight through the center. The circumference of a circle is the distance around.

Since our children are far too young to have any concept of Pi, I wouldn’t spend too much time talking about it.  I may, however, serve some wonderful fruit pie for snack on Thursday- and smile to myself.

As we bring in the month of November, you may be able to find pumpkins at closeout special prices- I mean CHEAP.  Once Halloween is over, people are generally finished buying pumpkins, which makes them the perfect early childhood item for exploration.

Many of the ideas about apples we explored during September can be revisited with pumpkins.  Click here and here and here for those ideas. Instead of making apple sauce, you can make pumpkin butter, but everything else fits.

Since pumpkins are so much bigger than apples, children may be really excited to get their very own pumpkin to explore.  It  might be really fun to pull out the bathroom scale and show the children how to weigh their pumpkins.  You can then graph their weights and put them in order from lightest to heaviest.  The most interesting part of this experiment is that you may find that the biggest pumpkin (the one that LOOKS the biggest) does not weigh the most.  This will create a great discussion with the children.

This book tells the story of a pumpkin so big that the witch who grew it cannot lift it so she asks all of her friends to help her.

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.