Building and Describing Solids

Overview

This is lesson 6 of 10 in the unit Shape, Space and Measure. Students build three-dimensional solids, identify and count faces, edges and vertices, and explain how changing one feature can change the solid. The lesson develops mathematical language, visual-spatial reasoning and the ability to justify ideas using models.

Learning intentions

• WALT build and identify common three-dimensional solids.
• WALT describe solids using the words faces, edges and vertices.
• WALT compare models and explain how changing a feature affects the solid.
• WALT record our observations clearly and explain our thinking.

Success criteria

• I can build a solid from cubes, construction materials or a net.
• I can correctly identify and count its faces, edges and vertices.
• I can compare two solids using mathematical language.
• I can explain how a change to a model changes, or does not change, its properties.

Curriculum links

• Mathematics and Statistics — Shape, space and measure: exploring and describing three-dimensional objects.
• Mathematics and Statistics — communicating mathematical ideas using representations, oral explanations and recording.
• Mathsteasers: higher-order thinking, challenge and deepening understanding for advanced learners.
• Mathsteasers / Alignment: connecting practical challenges with relevant mathematical learning.

Lesson structure (45 minutes)

1. 0–5 min · Hook and revisit. Teacher displays the opening solids comparison showing two different-looking block models and asks, “Are these the same solid? How could we prove it?” Students discuss with a partner, recall the meanings of face, edge and vertex, and share one observation.

2. 5–12 min · Explicit teaching. Teacher uses the vocabulary and worked-example slides to model a cube and a rectangular prism, tracing each face, edge and vertex carefully and recording totals. Students use their fingers or a small model to locate each feature, then help check a class table; emphasise that a vertex is a corner where edges meet and that an edge is a straight boundary.

3. 12–17 min · Demonstration and instructions. Teacher demonstrates building a solid with linking cubes or construction materials, then shows how to use the 3D shape nets pack as an alternative building method. Teacher introduces the build-and-record challenge worksheet, explains the recording table and assigns partner roles: builder and recorder, swapping halfway. Students predict the features of one model before beginning.

4. 17–32 min · Build-and-record challenge. Teacher circulates, asks “How do you know?” and checks that students count systematically rather than recounting the same feature; provide models or partially completed tables when needed. Pairs build at least two solids, record the number of faces, edges and vertices on the build-and-record challenge worksheet, and sketch or name each model.

5. 32–40 min · Compare and explain. Teacher pauses the class and uses the comparison and discussion slides to present prompts such as, “What changed when one cube was added?” and “Can two models have the same number of cubes but different properties?” Students compare their models with another pair, identify one similarity and one difference, and explain the effect of changing a feature using a sentence such as, “When we changed ____, the number of ____ changed because ____.”

6. 40–45 min · Plenary and assessment. Teacher displays the plenary and exit-question slide and invites several pairs to justify an answer. Students complete the final reflection on the build-and-record challenge worksheet: draw or name one solid, record its faces, edges and vertices, and answer, “How did changing one feature affect your solid?” Students hand in the worksheet as they leave.

Resources

• Linking cubes, construction materials or other interlocking building materials
• the Building and Describing Solids slide deck
• the build-and-record challenge worksheet
• the 3D shape nets pack
• Sample cube and rectangular prism models
• Large class recording chart or whiteboard
• Pencils, rulers and coloured pens
• Word cards or visual prompts for face, edge and vertex

Assessment

• During modelling, listen for accurate use of face, edge and vertex and ask students to point to each feature on a model.
• During the challenge, check whether students count systematically, record accurately and explain their comparisons; photograph or note useful examples and misconceptions.
• Use the final worksheet reflection to identify who can connect a change in a model with a change in its properties.

Differentiation

• Provide a cube, rectangular prism and other completed model examples for students who need a visual reference. Use colour coding or small stickers to mark one face, edge and vertex before students count independently.
• Give selected students a partially completed table, a smaller building target and sentence starters: “My solid has…”, “I notice…”, and “It changed because…”.
• Use predictable partner roles, clear step-by-step instructions and a visual timer. Allow students with dyslexia or other learning barriers to dictate observations, use a scribe, or record by drawing and labelling rather than writing full sentences.
• For autistic students, show the sequence of the activity in advance, offer a choice of building material, and provide a quieter workspace or reduced-distraction option.
• Extend confident students by designing a solid that meets given criteria, such as “12 edges, 8 vertices” or “more than one solid made from the same number of cubes”, then proving that it meets the criteria.