Math Monday::Halloween Symmetry!

With Halloween being not to far away, at least for us here in the USA (which reminds me of a hysterical story involving our attempt to trick or treat with the kids when we lived in Budapest…but I’ll save that for later…), we’ve been crafting like crazy. Also, the leaves are almost all off the trees, so I thought I’d post a Math Monday using symmetry before all the leaves are gone, baby, gone.

First, paper cut symmetry…it’s the same principle as making paper snowflakes…the idea that you can fold paper, cut it, and it creates a symmetrical pattern. This is a fun one–take square pieces of paper, we used 8 by 8 decorated pattern paper, but even construction paper will work. Since this is symmetry, you’ll fold it in half. On one half of the paper, draw half your shape:

We drew:
pumpkins
ghosts
cats
spiders

Then, once you’ve done that, you can cut around the mark:

…and open the paper up again to see how it looks! Here’s a bat…

and a cat from Naturalist:

There is something called a ‘line of symmetry’ which is illustrated perfectly when the figures are unfolded. It’s the line in the middle that divides a shape where the two sides on either side match.

A great video to watch with your kids on symmetry and line of symmetry is through this link.

A quick note: if your child struggles with writing, it may be frustrating for them to draw the image and/or cut it out. Golfer didn’t enjoy that part at all. So I let him direct me in the drawing and cutting, and then he got to take our images and tape them to all the windows:

Something else we’ve been doing is the good old leaf rubbings. Everyone goes outside and pics a few (or more!) of their favorite fallen leaves. They can’t be too brittle, or it won’t work…so, leaves that aren’t too dry yet.

Bring the leaves inside, lay them on a piece of paper and place another sheet of paper over the top. Get a crayon in a nice fall color, unwrap it, and use the side of it to gently rub over the paper. This will give a nice rubbing of the veins and outline of the leaf. Point out the lines of symmetry and talk generally about how one side of the leaf is so similar to the other. Do this for every leaf, varying the fall colors you use, then cut them out and tape them everywhere.

This may lead to an interesting observation about all the symmetry there is in nature (if the video hadn’t already sparked this discussion!). If you child is interested, go on a photo safari for nature symmetry. (Symmetry in Nature) Sassy and I did this, but my card reader is about 2 seconds away from not working anymore, and it failed to upload any of those pictures. But I’m sure you know what I mean! Snap a picture of everything that you see outside that is symmetrical.

This is a perfect ending to a fun time…especially if you’re coming in from outside where it may be cold–a great excuse to put on a pot of hot chocolate and look around at all the lovely decorations you have scattered all over your house!