Area versus perimeter was again problematic to a student in grade 8 yesterday. Please – if anyone is reading this post, take a string with you and a piece of squared paper next time you meet a child.
If you can take a good pair of scissors then it’s even better.
Please draw the shape of anything (of any shape that is meaningful to the child). Ask the question: “how much string do I need do I need to go around it? or how long is the wall around the room? or how much must you walk to go around the shape?” We just take the string and coil it all around the shape – in Math, it’s called perimeter: peri because it goes around and meter because it’s a measurement. One step ore would be to measure the string against a ruler and come up with a number.
How many floor tiles will be necessary to tile the room? Just count the squares. That’s the area, the amount of bare space. This is where you cut squares and place them side by side in the drawn room or other rectangular shape that speaks to the child. If your shape is a circle, then stick them side by side and then cut the squares into little bits, keeping a tally of how many you are using.
Invite every child you can to build with lego bricks; talk about area and perimeter. Cover the ground with square tiles. Go to the hardware store with the children. Tell them what you are looking for and why. Give examples of length. Talk about length being 1D (one dimensional) Go to the fabric store and make some drapes; show the process of measuring for them. Talk about the space to be covered: talk about 2D (two dimensional). I don’t know how it is that 5 years before university I get students who haven’t experienced this.
Please let’s never talk about formulae – who cares? If a child knows what she’s/he’s counting that’s enough. Only when the child has experienced this can he or she gain from the video below.