This week in second grade, we are embarking on our geometry unit in math. The first topic is identifying shapes and their special characteristics. I love teaching properties of shapes because you can incorporate so many fun, hands-on activities. Even the kids who don’t like math much really enjoy learning about shapes.

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## A Lesson Plan for Teaching Properties of Shapes

When teaching properties of shapes, my objective is for students to recognize regular polygons by their straight, closed sides. They will also classify different shapes as quadrilaterals or not and describe the geometric properties of different shapes.

My lesson plan for teaching properties of shapes consists of:

- Read a book to generate interest and introduce math vocabulary
- Explicitly teach vocabulary
- Use a graphic organizer to describe a shape
- Create a table summarizing the basic properties of shapes
- Determine which shapes are quadrilaterals
- Formative Assessment: sort and categorize shapes
- Culminating (FUN) Activity: shape building

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Let’s take a closer look at each part of this math lesson:

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### STEP 1 – READ ALOUD

When teaching properties of shapes, I love to start off with “The Greedy Triangle” by Marilyn Burns. This is the perfect activity to introduce our geometry unit because it talks about math concepts in a really fun way.

The story follows the adventures of a triangle who becomes unhappy with its three-sided shape and dreams of becoming something more. With the help of an enchanted shape-shifter, the triangle embarks on a journey, transforming into various polygons with an increasing number of sides.

As the triangle changes into a quadrilateral, pentagon, and beyond, it discovers the advantages and disadvantages of each shape. Eventually the triangle realizes that being content with who you are is more important than constantly seeking more and more.

I like how the book introduces students to basic math concepts such as different geometric shapes and angles while also teaching an important life lesson.

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### STEP 2 – TEACH VOCABULARY

The read-aloud introduces students to some math vocabulary, but it still needs to be explicitly taught. To do this, I use some cards from my geometry word wall.

To be successful with the activities in this lessons, students need to know the following shapes and math words:

- square
- rectangle
- circle
- triangle
- pentagon
- hexagon
- octagon
- trapezoid
- rhombus
- quadrilateral
- polygon
- angle
- vertex
- side
- parallel

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As I introduce each new word, I add it to our math word wall so students can refer to them as needed. Students should be able to name shapes before this lesson and will be able to describe their attributes after this lesson.

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### STEP 3 – USE A GRAPHIC ORGANIZER

The next step in teaching properties of shapes is to have students practice describing 2-dimensional shapes and recording their observations on a graphic organizer. For this activity, I use a Circle Map.

First, I model how to use a Circle Map. Then students try it independently with a shape of their choice. For this lesson, I display pictures of shapes using those geometry word wall cards I mentioned; so students can look back at them while completing their graphic organizers.

Another option is to pass out attribute blocks which are a type of math manipulative found in a lot of primary classrooms. These come with a variety of three-dimensional shapes, so students can get a lot of practice comparing them and describing shape attributes.

As the students complete their graphic organizers, I look for them to include the name of the shape, the number of sides, whether they are straight sides and/or equal sides, and the number of angles or vertices. They should describe a flat plane figure as we are not working 3-D shapes yet.

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### STEP 4 – CREATE A TABLE

The next step in teaching properties of shapes is to come together with the completed circle maps and transfer the information students collected onto a table of shape attributes. This lets us easily compare and contrast the different shapes.

I have the students sit in small groups according to which shape they chose to describe. As we create the table, each group provides the pertinent information about their shape.

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### STEP 5 – IDENTIFY QUADRILATERALS

After summarizing the properties of basic shapes on our table, it’s easy to determine which shapes are quadrilaterals. Referring back to the math word wall, students can see that the definition of a quadrilateral is any closed, 2-dimensional figure with four straight sides.

Next, I bring out my shape posters. These are simple pictures of basic flat shapes. On my whiteboard I write two headings: **QUADRILATERALS** and **NON QUADRILATERALS**.

I hold up each shape poster and we go down a checklist to determine which heading it should be placed under:

- Is it a flat, 2-dimensional shape?
- Is it closed?
- Does it have 4 sides?
- Are all the sides straight?

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If we say yes to all of those questions, the poster goes under the QUADRILATERAL heading.

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### STEP 6 – SORT AND CATEGORIZE SHAPES

Like any lesson, when teaching properties of shapes, you need to determine whether the objective was met. Did the students learn what you wanted them to? For that, you need a formative assessment.

For this lesson, I use a cut-and-paste worksheet which asks students to sort and categorize shapes based on their properties.

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First, I pass out a copy of the worksheet to each student. I point out where it says POLYGONS at the top because all of the shapes we have been working with are polygons. I also point out that there is a box that says NON-POLYGONS. The polygon box is further divided into two sections: one for quadrilaterals and one for non-quadrilaterals.

At the bottom are some pictures of shapes to cut out. I explain that they will be sorting the pictures and gluing them into the correct category on the worksheet.

Students can look at our geometry word wall for helps, but that’s okay. This is not a summative assessment. I don’t expect them to have memorized the definitions of shapes at this point. I’m looking to see if these second graders can look at the properties of each shape and classify them.

The graphic organizer on this worksheet can be a little tricky for young children because it includes both examples and non-examples. So I guide them without giving away the answers.

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### STEP 7 – SHAPE BUILDING ACTIVITY

I love hands-on activities in math! It’s so important in elementary school. When teaching properties of shapes, I like to finish up with an activity in which the whole class will build their own equilateral triangles, quadrilaterals, and pentagon shapes using marshmallows and toothpicks.

This isn’t really part of my lesson. It’s just a culminating activity that lets students further explore and build their knowledge of shapes. The toothpicks serve as straight lines for the sides and the marshmallows work as vertices or corners. It’s a great way to make math a little more fun!

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After the students spend a little time building, I give them sticky notes to label the shapes with their proper names. They also write down how many sides and vertices the shape has. As they are doing this, I circulate through the room and look for any non-symmetrical polygons to show the class that not all shapes have a name.

I hope this blog post has given you some new ideas and fun activities for teaching properties of shapes in your own classroom!