Mirror images

This past week, we studied congruency and symmetry. Congruency tends to be relatively simple for the kids. Same size, same shape. That's pretty easy to remember. What often throws them is when the shapes are rotated. Especially when the shapes are triangles.

But symmetry really throws them for a loop. When I would draw a shape and ask how many lines of symmetry it had, several of them would just count the sides and give me that answer. Several would always say 2 (vertical and horizontal). And several would find lines that weren't symmetrical at all.

Diagonal lines are especially hard for the kids to judge. Though I've emphasized to them that they can and should TURN their paper, to make the line look vertical, they usually don't. Also, they confuse it with congruency, so if the two sides of the line are the same size and same shape, they go with symmetry. Even if the two sides aren't mirror images. For instance, the diagonal line of a rectangle DOES split the rectangle into two congruent triangles. However, this line is not a line of symmetry, because folding the shape on the line would not yield a perfect matchup.

Friday's test results weren't too bad, but there is clearly still a lot of work to be done, especially in some dire cases. (Where kids still don't even know their basic shapes.)

At least I haven't had anyone yet this year call it a "line of cemetery."

Getting back into shape

Last week, we went over 2 and 3-dimensional shapes in class. This is usually a fun, though confusing topic for the kids. They enjoy identifying shapes -- they just tend to identify them incorrectly for quite a while. For instance, anything that is round, they want to call either a circle or a sphere. Clocks, tires, pennies. If it's a long skinny cylinder, they know it's a cylinder. But the short and squat cylinders, like the aforementioned clock et al, they see round and think sphere.

But we're getting there. Even though Thursday was the coldest day of the year so far, we took our designated "shapes walk" outside. The kids had made flip books with doors for 6 of the major 3-dimensional shapes, and we walked around the sidewalk outside of the school, looking for real-life objects that met those shapes.

In addition to being cold, Thursday was also a short day, because teachers had extended horizontal planning in the afternoon, so we didn't get to walk a complete circuit around the school. It's a shame, because there's a perfectly cone-shaped tree on one side, and pyramids on the playground.

Nevertheless, the kids got a thrill from seeing telephone poles, roofs, fire hydrants, stop signs, etc, and shouting out what shape they were.

At first, some of them wanted to spend more time complaining about how cold it was rather than looking for shapes. I told them to suck it up. OK, well, not in those words.

I asked if they would rather freeze their spheres off looking for shapes or slink our sorry cylinders back into the rectangular prism and sit on our butts til they were 2-dimensional.

OK, so I didn't use THOSE words either. But ultimately, it was agreed upon that a bit of cold was a fair trade off for the great outdoors.

And the really great thing about the week? Nobody got any toothpicks stuck in their ass!

The shape of things to come

Today was truly an exercise in patience. As usual, I found myself wanting...

Since we discussed and classified 2-dimensional shapes yesterday -- and the explanation for yesterday's debacle was merely, "I sat on it" -- today we talked about 3-dimensional shapes. Not only did we talk about them, I gave each student a net to cut out and paste together to create a geometric figure.

My morning class (MUCH easier to handle) did pretty well. The only real problem was convincing the kids that their finished product should look like one of the pre-made shapes on my counter, and NOT like a wadded up Kleenex. Sure, a wadded up Kleenex is, technically, three-dimensional, but that's not the point of the lesson.

Then came the afternoon class. Before I could even get the kids started on cutting out the nets, I had to stop several times to review scissor safety and how you do NOT clip the shears back and forth in front of your face. I then had to place not one, but TWO kids in time out for immediately clipping the shears back and forth in front of their faces.

After the kids had created their figures, I began the unenviable task of coaxing them to explore the attributes. How many faces? What 2-D shapes are the faces? How many edges? How many vertices?

As usual, I had about 4 kids that were actively participating and trying to answer the questions while the others did their best showroom window mannequin impersonation.

Finally, the end of the day came around and it was time to dismiss the kids. As I called them to line up, the first boy in line held out the metal part of a pen that holds the tip in place. He said, "Look, this is a cone."

I tend to be a very impatient person and I will be the first to declare that I am SOO ready for a break from this year, this school, these kids.

However, in that moment right before dismissal, one child demonstrated that he HAD learned something today and that he could apply that knowledge to a real-world object.

It's always nice to be reassured that SOMETHING is working...