Help students practice origami to develop a knowledge of geometric properties. This is meant for a second-grade class for the duration of one class period, 45-60 minutes.

**Key Vocabulary: **symmetry, triangle, square, rectangle

### Materials

- origami paper or wrapping paper, cut into squares of 8 x 8
- a class set of 8.5 x 11 paper

### Objectives

Students will use origami to develop an understanding of geometric properties.

### Standards Met

2.G.1. Recognize and draw shapes having specified attributes, such as a given number of angles or a given number of equal faces. Identify triangles, quadrilaterals, pentagons, hexagons, and cubes.

### Lesson Introduction

Show students how to make a paper airplane using their squares of paper. Give them a few minutes to fly these around the classroom (or better yet, a multipurpose room or outside) and get the sillies out.

### Step-By-Step Procedure

- Once the airplanes are gone (or confiscated), tell students that math and art are combined in the traditional Japanese art of origami. Paper folding has been around for hundreds of years, and there is much geometry to be found in this beautiful art.
- Read
*The Paper Crane*to them before starting the lesson. If this book can't be found in your school or local library, find another picture book that features origami. The goal here is to give students a visual image of origami so that they know what they'll be creating in the lesson. - Visit a website, or use the book you selected for the class to find an easy origami design. You can project these steps for students, or just refer to the instructions as you go, but this boat is a very easy first step.
- Rather than square paper, which you usually need for origami designs, the boat referenced above begins with rectangles. Pass one sheet of paper out to each student.
- As students begin to fold, using this method for the origami boat, stop them at each step to talk about the geometry involved. First of all, they are starting with a rectangle. Then they are folding their rectangle in half. Have them open it up so that they can see the line of symmetry, then fold it again.

- When they reach the step where they are folding down the two triangles, tell them that those triangles are congruent, which means they are the same size and shape.
- When they are bringing the sides of the hat together to make a square, review this with students. It is fascinating to see shapes change with a little folding here and there, and they have just changed a hat shape into a square. You can also highlight the line of symmetry down the center of the square.
- Create another figure with your students. If they have reached the point where you think they are able to make their own, you can allow them to choose from a variety of designs.

### Homework/Assessment

Since this lesson is designed for a review or introduction to some geometry concepts, no homework is required. For fun, you can send the instructions for another shape home with a student and see if they can complete an origami figure with their families.

### Evaluation

This lesson should be part of a larger unit on geometry, and other discussions lend themselves to better assessments of geometry knowledge. However, in a future lesson, students may be able to teach an origami shape to a small group of theirs, and you can observe and record the geometry language that they are using to teach the “lesson.”