Describing Properties of 2D Shapes (Sides & Vertices)

Active learning helps Year 1 students connect abstract properties of 3D shapes to real-world objects. Hands-on exploration lets them feel, turn, and compare shapes, which builds stronger memory than worksheets alone.

• Year 1
• Mathematics
• 3 activities
• 15 min–25 min

Learning Objectives

1. Identify and count the number of sides and vertices on common 2D shapes.
2. Compare a square and a rectangle based on their number of sides and vertices.
3. Explain why a circle has no straight sides or vertices.
4. Construct a shape with a specified number of straight sides and vertices.

Inquiry Circle

⏱ 20 min·Small Groups

Inquiry Circle: Will it Roll or Stack?

Groups are given a set of 3D objects and a ramp. They must predict which shapes will roll, slide, or stack, test their theories, and then record their findings on a large group chart.

Prepare & details

Compare a square and a rectangle based on their properties.

Facilitation Tip: During Collaborative Investigation: Will it Roll or Stack?, provide real objects rather than pictures so students can physically test each shape's movement.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Think-Pair-Share

⏱ 15 min·Pairs

Think-Pair-Share: 3D Shape Builders

Pairs are given playdough and straws. One student asks for a shape with '6 square faces'. The other must build it. They then discuss which parts are the 'faces' and which are the 'edges'.

Prepare & details

Explain why a circle has no straight sides or vertices.

Facilitation Tip: During Think-Pair-Share: 3D Shape Builders, circulate and prompt pairs with questions like 'How many faces does your pyramid have?' to keep them focused on properties.

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Gallery Walk

⏱ 25 min·Whole Class

Gallery Walk: The 3D City

Students use recycled materials (boxes, tubes, balls) to build a model city. They then walk around the 'city' and use sticky notes to label the 3D shapes they see used in the buildings.

Prepare & details

Construct a shape with three sides and three vertices.

Facilitation Tip: During Gallery Walk: The 3D City, assign each student a shape to explain to visitors, which builds confidence and reinforces vocabulary.

Setup: Wall space or tables arranged around room perimeter

Materials: Large paper/poster boards, Markers, Sticky notes for feedback

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

Teaching This Topic

Start with physical models to avoid confusion between 2D and 3D terms. Avoid rushing to abstract drawings; let students manipulate shapes first. Research shows that touching and moving objects improves spatial reasoning more than visual-only tasks. Use clear, consistent language like 'flat face' and 'curved surface' to prevent misconceptions from forming early.

What to Expect

By the end of these activities, students will name common 3D shapes accurately, describe their properties using vocabulary like flat, curved, roll, and stack, and connect 2D faces to 3D solids in their environment.

Watch Out for These Misconceptions

Common Misconception

During Collaborative Investigation: Will it Roll or Stack?, watch for students calling a sphere a 'circle' or a cube a 'square'.

What to Teach Instead

Prompt students to pick up the shape and ask, 'Is this flat like a piece of paper or can I hold it in my hand like a ball?' Use the physical difference to redirect their vocabulary.

Common Misconception

During Gallery Walk: The 3D City, watch for students struggling to classify shapes with curved surfaces as 3D.

What to Teach Instead

Use the sorting hoop to divide shapes into three groups: only flat faces, only curved surfaces, and both. Ask students to explain why a sphere belongs in the curved surface group and how that makes it 3D.

Assessment Ideas

Quick Check

After Collaborative Investigation: Will it Roll or Stack?, show students cards with different 2D shapes. Ask them to hold up fingers to indicate the number of sides and vertices for each shape. Observe accuracy and provide immediate feedback by modeling rolling or stacking actions with the corresponding 3D solid.

Exit Ticket

After Think-Pair-Share: 3D Shape Builders, give each student a worksheet with a square, a rectangle, and a circle. Ask them to write the number of sides and vertices for the square and rectangle, and to explain why the circle has neither.

Discussion Prompt

During Gallery Walk: The 3D City, present two shapes, for example, a square-based pyramid and a triangular-based pyramid. Ask students: 'How are these shapes the same in terms of sides and vertices? How are they different?' Listen for precise vocabulary and comparative reasoning.

Extensions & Scaffolding

• Challenge: Ask students to build a structure using only shapes that stack, then only shapes that roll.
• Scaffolding: Provide a word bank with 'roll', 'stack', 'flat', 'curved', and 'face' for students to reference during discussions.
• Deeper exploration: Have students trace the faces of a cube onto paper and label each 2D shape to connect 2D and 3D concepts.

Key Vocabulary

side	A straight line segment that forms part of the boundary of a 2D shape.
vertex	A point where two or more sides of a 2D shape meet. Plural: vertices.
straight side	A side that forms a perfectly straight line, not curved.
curved side	A side that bends or curves, like the edge of a circle.