Next week is the big day... time for my formal observation. Ugh, I just hate this time of year! But not because I question my own teaching skills. It's the kids and their inability to act like humans when another adult enters the room. Why is it that they all lose their minds as soon as the principal shows her face? Don't get me wrong... I have a lovely class this year. In fact, I like them so much that I'm hoping to loop up to third grade with them. They are sweet and cute and pretty darn smart! But Lord help me, as soon as another teacher (or God forbid, an administrator) comes in, you would think they'd been raised in barns. Anyway, it's time for me to plan a lesson for my observation. Since we are just starting our geometry unit in math, I will be teaching a lesson on the properties of 2-D shapes. But as I sit here planning for the dog and pony show, I'm second guessing myself.

Why, you ask? Because my lesson plan involves toothpicks.... second graders and toothpicks. But more on that later.

## A Lesson Plan for Teaching the Properties of Shapes

The objective of this lesson will be for my 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.

So far, my plan for teaching this math concept 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

Let's take a closer look at each part of this math lesson:
**Read Aloud**
The book I'll be reading to the class is "The Greedy Triangle" by Marilyn Burns. This is really the perfect activity to start our geometry unit because it introduces 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.

**Teach Vocabulary**
The read-aloud introduces students to some math vocabulary, but it still needs to be explicitly taught. To do this, I will 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

As I introduce each new word, I will 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.

**Use a Graphic Organizer**
The next step in this lesson is to have students practice describing 2-dimensional shapes and recording their observations on a graphic organizer. For this activity I am using a Circle Map.

First, I model how to use a Circle Map. Then students will try it independently with a shape of their choice. For this lesson, I have pictures of shapes on 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 will be looking 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.

**Create a Table**

The next step in this lesson plan is to come together with the completed circle maps and transfer the information students collected onto a table of shape attributes. This will easily let us all compare and contrast the different shapes.

To do this efficiently, I have the students sit in small groups according to which shape they chose to describe. As we create the table, each group will provide the pertinent information about their shape.

**Identify Quadrilaterals**

Now that we have summarized the properties of basic shapes on our table, it easy to determine which of the 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.
This when I bring out my shape posters. These are simple pictures of basic flat shapes. On my whiteboard I write two big 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 of the sides straight?

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

**Sort and Categorize Shapes**

This is my formative assessment - the last real part of the lesson when I get to see if my students have met the objectives.

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 of the worksheet 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.

My geometry word wall cards are still hanging in the room and sure, they can look at them for help. 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 just looking to see that these second graders can look at the properties of each shape and classify them.

Now 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.

After letting the kids cut out all the shapes, I tell them to look for all the polygons and put them into one pile. Then, whatever shapes are left over are the non-polygons and should be glued under that heading.

Once they are finished gluing, I do the same thing with the rest of the shapes. The students look at whatever shapes they have left and pick out the ones that are not quadrilaterals. These get glued under the non-quadrilaterals heading. Now all that remains are the quadrilaterals.

The worksheet I use for this formative assessment is part of this resource: Properties of Shapes Classifying Quadrilaterals & Polygons

### Shape Building Activity

I love hands-on activities in math! It's so important in elementary school. So to finish up our lesson, the whole class will build their own equilateral triangles, quadrilaterals, and pentagon shapes using marshmallows and TOOTHPICKS. What was that? Did you say toothpicks? As in small, sharp projectiles made of wood? Okay, so this is where the second guessing comes in. Have I lost my freaking mind?!!! Let's just list the ways this could go oh-so-wrong...

The 7-year olds could poke themselves in the eye and be blinded for life.

They might jab themselves and end up with MRSA or some other horrid affliction.

They might accidentally swallow one and pierce their internal organs.

They could pretty easily use the marshmallows and toothpicks to build a giant phallic symbol.

I could be sued and/or lose my teaching license for any of the above happenings.

So what should I do? Use the toothpicks, of course! What's an effective lesson without a little danger, right? 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!

After the students spend a little time building, I give them sticky notes to label the shapes they made 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 that you can use to teach the properties of shapes in your own classroom!

Download this free polygons graphic organizer that can be used to teach different types of shapes and their properties.

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