Identifying Plane Shapes

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SWBAT identify and categorize plane shapes by defining attributes.

Big Idea

First graders begin to learn about plane shapes in Kindergarten. This lesson will serve as review of plane shapes' characteristics and extend into practice in categorizing shapes by defining attributes.

Rev Them Up

7 minutes

The CCSS have supplied a more in-depth goal for my first graders to master than the previous state supplied standard of just being able to identify plane shapes. CCSS expects first graders to be able to distinguish between defining and non-defining attributes of shapes and categorize them accordingly (1.G.A.1). Defining attributes have to do with the number of sides and angles, like a triangle has 3 sides and 3 vertices, yet a circle has none.  Non-defining would be one is larger than another or the colors are the same. I want them to see that even if they are different colors or sizes, they are still that category of shape. The defining attributes of that shape create a structure we can use to categorize shapes (MP7).

I will get my students thinking about shapes by playing a game of I Spy with them. I will begin with basic review of shape concepts from kindergarden by giving clues such as:

  • I Spy something that is a rectangle and we can use it to tell time. (Our wall clock)
  • I Spy something that is a circle and helps to spell my name on the bulletin board. (Letter O)

Then I will move to something that is more difficult:

  • I Spy something that is a triangle and Katie gave it to me as a gift. (Dress on an ornament)

These examples are specific to my classroom and experiences my students have had. Please use these examples as ideas and personalize your own.

Check out the videos of our game of I Spy: segment 1 and segment 2.

I will play the game for a few minutes longer and move to the next activity.

Whole Group Interaction

10 minutes

Need: Cut at least two different sizes and colors for the following shapes; circle, square, rectangle, pentagon, triangle (shapes).

I will be using the cut shapes to help my students identify each shape's attributes. The ideas and vocabulary I want to make sure we cover are

  • Triangles have 3 sides and 3 corners.
  • Circles have 0 sides and 0 corners.
  • Rectangles have 4 sides and 4 corners.
  • Squares are a type of rectangle that has 4 equal sides and 4 equal corners.
  • Pentagons have 5 sides and 5 corners; and "pent" means 5.
  • Colors and size do not matter. The attributes of the shape do.
  • A side is a line that makes part of shape.
  • A corner is formed by two lines that connect.
  • A polygon is any shape that is closed, has straight lines and is on a flat plane. We will discuss which shapes qualify as a polygon. Make sure to watch the Intro polygon video of our discussion.

Make sure to cut two different shapes from the same color so you can make a point that they are the same color, but not the same shape. Also, make sure to cut the same shape, but make them different sizes, so you can point out that they are the same due to their attributes. During today's discussion I want my students to develop an understanding of the terms: corner, side, closed shape, straight lines, and polygon. In the next lesson, I will introduce the terms vertex and vertices to help describe the corners of flat plane shapes. The Common Core Standards were developed to allow our students to explain their thought processes and develop deeper mathematical understandings. Teaching them academic vocabulary will allow them to develop these skills.

Independent Practice

15 minutes

Print the Match up shapes worksheet and copy for each student.  Also, you will need construction paper of any color for each student.

Now my students will be practicing categorizing shapes on their own.  I will provide them with construction paper and the worksheet. Students will have to cut out the shape names and glue them in an orderly fashion on their paper.  I want them to attempt to organize their own data.  I will tell them to make sure I can tell what shapes they are matching to each name. Some of the shapes are shaded and some are different sizes, so they will have to think about the defining attributes of each shape to match them correctly. My students will cut and be getting things ready to complete their work. They must develop their own idea of how to organize their labels and shapes on the construction paper. You can watch this shapes video to see what happened in my classroom.


5 minutes

This is a beginning lesson in our shapes unit and I want it to end by giving my students an opportunity to summarize what we have discussed today. I will pose a question to the class, but I want my students to discuss their answers together in their groups. I have my desks formed in 5 pods, so my students will discuss their thoughts within their pods and select a speaker to share their answer.

What are the essential differences between a triangle and a circle?