Mathematics · Year 1 · Geometry and Spatial Sense · Spring Term

Describing Properties of 2D Shapes (Sides & Vertices)

Identifying and counting sides and vertices of common 2D shapes.

• National Curriculum Attainment Targets
• KS1: Mathematics - Geometry: Properties of Shapes

About This Topic

Exploring 3D solids introduces Year 1 students to the three-dimensional world of geometry. The National Curriculum requires pupils to recognize and name common 3D shapes, including cuboids (including cubes), pyramids, and spheres. Students learn to describe these shapes by their properties, such as whether they can roll or stack, and by identifying the 2D shapes found on their faces.

This topic bridges the gap between abstract geometry and the physical environment. Understanding 3D shapes is essential for developing spatial reasoning and architectural thinking. It also helps children understand how objects interact, for example, why a ball rolls but a box does not. Students grasp this concept faster through structured discussion and peer explanation while physically handling and building with various solids.

Key Questions

1. Compare a square and a rectangle based on their properties.
2. Explain why a circle has no straight sides or vertices.
3. Construct a shape with three sides and three vertices.

Learning Objectives

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

Before You Start

Recognizing Common 2D Shapes

Why: Students need to be able to identify basic shapes like squares, circles, and triangles before they can describe their properties.

Counting to 10

Why: Accurate counting is essential for determining the number of sides and vertices on shapes.

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.

Watch Out for These Misconceptions

Common Misconception

Confusing 2D and 3D names

What to Teach Instead

Students often call a sphere a 'circle' or a cube a 'square'. Use physical models and ask 'Can I pick this up or is it flat?' to help them distinguish between a 2D drawing and a 3D solid.

Common Misconception

All 3D shapes have flat faces

What to Teach Instead

Children may struggle to classify spheres or cylinders as 3D because they have curved surfaces. Use a 'sorting hoop' to separate shapes with only flat faces, only curved surfaces, and those with both.

Active Learning Ideas

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.

20 min·Small Groups

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'.

15 min·Pairs

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.

25 min·Whole Class

Real-World Connections

• Architects use their understanding of 2D shapes to design floor plans, specifying the number of sides and corners for rooms and buildings.
• Graphic designers create logos and illustrations using basic 2D shapes, carefully considering the number of sides and vertices to achieve specific visual effects.

Assessment Ideas

Quick Check

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.

Exit Ticket

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

Present two shapes, for example, a square and a rhombus. 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.

Frequently Asked Questions

What 3D shapes are taught in Year 1?

Year 1 students focus on cubes, cuboids, pyramids, and spheres. They may also encounter cylinders and cones as they explore the properties of rolling and stacking.

How can active learning help students understand 3D shapes?

Active learning is essential for 3D geometry because these shapes are meant to be handled. Building with blocks, testing objects on ramps, or creating playdough models allows students to feel the vertices and faces. These physical experiences make the mathematical vocabulary (like 'surface' or 'vertex') much more meaningful and easier to remember.

What is the difference between a face and a side?

In 3D shapes, we use the term 'face' for the flat or curved surfaces. 'Side' is usually reserved for the edges of 2D shapes. Teaching the correct term 'face' early helps avoid confusion as they progress in geometry.

How can I help my child identify 3D shapes?

Use groceries! A tin of beans is a cylinder, a box of tissues is a cuboid, and an orange is a sphere. Ask them to try and stack the items to see which ones work best, which reinforces their understanding of shape properties.