Geometry can be a fickle thing to teach. In some ways, it is super simple. I mean, it IS just shapes!! However, in others it can be very difficult. First of all, how in depth should you get? What do your kids need to know? Secondly, oh the VOCABULARY! GAH! SO.MANY.TERMS.
Let's dive in and take a closer look at 2D (plane) shapes. Next post will focus on 3D shapes!
What Do the Standards Expect?
Georgia has developed a set of frameworks that reviews each standard and gives ideas and resources for each math concept. It also breaks the standard down so that teachers can be sure they are addressing what the standard expects from students. I liked this version because I thought it was very user friendly for teachers.
I cut and paste student expectations into a "prettier" and easier to read document. You are more than welcome to download it here, free.
The list of end of unit expectations looks long, but many of them piggy back on each other. It is very clear that students need to be able to understand and use the attributes of plane and solid shapes...which is a whole lotta vocabulary!
So how can you help teach concepts and solidify understanding of vocabulary? Let's about the lessons.
What Should I Be Teaching?
While the standard may not explicitly mention polygons, it is embedded in the standard. Students will have to know what a polygon is to even begin understanding 2D shapes. A polygon is a 2D shapes made of straight lines and is closed. A sort is a simple, but meaningful way to help students understand and differentiate between a polygon and not a polygon.
Then, students can apply their learning to plane shapes and begin to learn the basic plane shapes and the attributes (sides, corners, and angles). A great book to introduce plane shapes is the book The Greedy Triangle.
This is a longer book, and I usually do not read longer books as part of my math mini lesson during math workshop. You can read more about that here. However, this was a book I ALWAYS made time for. I usually read this book aloud on Fridays, when I did not follow the math workshop model.
Students were each given a geoboard and rubber bands. While I was reading, the geoboards has to stay on the floor, and students kept their hands in their laps so they could listen. In the book, the main character (The Greedy Triangle) is bored and wishes to change shapes. He changes into different plane shapes. As the character adds new angles and changes into a new polygon, students make the polygon on their geoboards and record it on the anchor chart.
These anchor charts may not be pinterest perfect, but it was the real world in my classroom! These are the charts we made as we read the book. I tried to call multiple students up to draw their shapes so other students could see that a hexagon, for example, could look different!
Students can practice novel ways of creating and identifying 2D shapes. Some ideas are:
- Creating plane shapes with playdoh and Popsicle sticks
- Gluing toothpicks in 2D shapes
- Sorting and graphing shapes
- Finding 2D shapes in the real world magazine pictures
After students become comfortable with the terms sides, corners, angles, you can introduce the concept that several plane shapes are quadrilaterals. This is another activity that is great for sorting.
It also leads well in to composing and decomposing 2D shapes. This is just a fancy way of saying what shapes make a hexagon or an octagon. Pattern blocks are wonderful for teaching composing and decomposing plane shapes. A fantastic (and hands-on) way to teach this is by having students stack the pattern blocks on top of each other. This way they can see that the shapes are exactly made by the blocks on top.
How Can I Deepen Student Thinking?
One of my favorite activities to challenge students is a riddle sort of activities. My school had a large pack of plastic polygons. If you don't have access the plastic polygons, you can get a printable set of polygons here from John Van De Walle (as well as a million other blacklines). Please note that all the 5 sided polygons are on the same page if you choose to use different color copy paper when printing. The colors might give the shape away ;)!
Lay the shapes out and sit the class in a circle around the shapes. Students will play a guessing game. Mentally choose a a shape and give students clues. For example, "My magic shape has more than 4 sides." Call on students to get rid of the shapes that don't fit the magic shape rules (triangles and quadrilaterals). You can use all kinds of clues to sharpen math thinking in general ("It has the same number of angles as the value of a nickel."). My kids loved this game. Make sure that when you pick the magic shape, there is only one like it (in this example, only one pentagon)! LOL
How can I apply this in my classroom?
Ready to turn around and try some of the of these activities? Grab your supplies and get ready!
Want the activities shared in this post and even MORE printables? Check out my Geometry Unit- Everything You Need and More!