Class 6 NCERT bridge course Answers Activity W3.4 Creating Patterns and Designs with Rotational and Reflection Symmetry

 Creating patterns and designs with rotational and reflection symmetry 

◻Symmetry is a property where one shape or arrangement can be transformed into another that looks the same. 

Activity W3.4  Creating Patterns and Designs with Rotational and Reflection Symmetry

 ● Provide students with various shapes such as squares, triangles, and stars etc. 

 Ask them to rotate each shape and observe if it looks the same after a certain amount of rotation.

 Encourage them to identify the amount of rotation to get a similar shape.

Activity W3.4: Creating Patterns and Designs with Rotational and Reflection Symmetry

Objective:

To help students understand rotational and reflection symmetry by using basic geometric shapes and observing how they behave when rotated or reflected.

What Is Symmetry?

Symmetry is when a shape or design looks the same after a transformation like flipping (reflection) or turning (rotation).

• Rotational Symmetry means a shape looks the same after being rotated (turned) by a certain angle.

• Reflection Symmetry (also called line symmetry) means one half of the shape is a mirror image of the other.

Materials Needed:

• Cut-outs of basic shapes: squares, equilateral triangles, rectangles, stars, circles

• A protractor (optional)

• Mirror strips (optional for reflection symmetry)

• Chart paper or plain grid sheets

• Colored pencils/markers

Part 1: Exploring Rotational Symmetry

 Instructions:

1. Give each student a shape cut-out.

2. Ask them to rotate the shape by 90°, 180°, 270°, and 360°.

3. At each step, check if the shape looks the same.

4. Record the angles where the shape matches its original position.

Example:

• Square:
  Rotational symmetry at 90°, 180°, 270°, and 360°
  → It has rotational symmetry of order 4.

• Equilateral Triangle:
  Rotational symmetry at 120°, 240°, 360°
  → Order 3.

• Star (5-pointed):
  Rotational symmetry every 72° (360° ÷ 5)
  → Order 5.

Part 2: Exploring Reflection Symmetry

Instructions:

1. Fold the shape in half in different directions.

2. If both halves match, then the shape has reflection symmetry along that fold.

3. Mark all possible lines of symmetry.

Example:

• Rectangle: 2 lines of symmetry (vertical and horizontal) 

  
  
  

• Square: 4 lines of symmetry

• Circle: Infinite lines of symmetry

• Heart: 1 vertical line of symmetry

Extension: Creating Symmetry-Based Designs

1. Use rotation and reflection to create rangoli-like patterns.

2. Repeat triangles or stars around a center point to form a mandala.

3. Fold and cut papers to make snowflake patterns using symmetry.

Shapes Set Geometric Shapes

• Rotational Symmetry Examples Rotational Symmetry Image

• Reflection Symmetry  Line Symmetry in Shapes

Discussion Questions:

• Which shapes have the most lines of symmetry?

• Does every shape have rotational symmetry?

• Can a shape have rotational symmetry but no reflection symmetry?

Conclusion:

By experimenting with common shapes, students develop a visual understanding of both reflection and rotational symmetry. These foundational geometry skills help in art, math, and logical reasoning.