Nets Become Solids

Overview

In this seventh lesson of the Shape, Space and Measure unit, students investigate how flat 2D nets can fold to create 3D objects. They build on previous learning about identifying and describing 2D and 3D shapes by predicting, testing and explaining which nets make cubes, cuboids and other solids.

Learning intentions

• WALT identify the 2D faces needed to make a 3D solid.
• WALT predict whether a net will fold into a cube, cuboid or another solid.
• WALT construct and test nets by cutting, folding and checking.
• WALT explain our mathematical thinking using observations about faces, edges and vertices.

Success criteria

• I can identify the faces in a net and the solid it may form.
• I can make a sensible prediction before folding.
• I can cut and fold carefully to test my prediction.
• I can explain why a net does or does not make a particular solid.

Curriculum links

• Mathematics and Statistics — spatial reasoning, shape and geometric thinking within Shape, Space and Measure.
• Mathsteasers — higher-order thinking questions that challenge learners and deepen understanding.
• Mathsteasers / Alignment — using challenge tasks that connect with classroom mathematics.
• Mathematical practices from the refreshed curriculum: noticing, predicting, testing, communicating and revising ideas.

Lesson structure (45 minutes)

1. 0–5 min · Hook and connect. Teacher displays a flat net and asks, “How could this become a box?” Open with the opening net challenge and invite students to turn-and-talk about what they notice from prior work with 3D shapes. Students identify possible faces, make an initial prediction and share a reason.

2. 5–12 min · Model the mathematics. Teacher demonstrates a cube net using the foldable net demonstration, deliberately folding one face at a time and modelling the language face, edge, vertex, fold line and net. Pause to ask which faces will meet and whether every face will close the solid. Students use their hands to show how faces might fold and rehearse an explanation with a partner.

3. 12–17 min · Predict before testing. Teacher introduces the investigation instructions on the prediction and investigation instructions and distributes the 3D shape nets pack to pairs. Students examine selected nets without folding, record or discuss whether each will form a cube, cuboid or another solid, and explain their predictions by counting and comparing faces.

4. 17–31 min · Cut, fold and test. Teacher supports safe, accurate cutting and folding, reminding students to follow solid fold lines and check whether faces meet. Students cut and fold selected nets from the 3D shape nets pack, test each prediction, and record “prediction”, “result” and “evidence” on the nets and solids investigation worksheet. Pairs change a failed net into a useful discussion rather than simply discarding it.

5. 31–39 min · Match and reason. Teacher uses the net-matching discussion slides to reveal examples gradually, asking, “What must be true for this net to close?” Students complete the matching section of the nets and solids investigation worksheet, matching nets to cubes, cuboids or other solids, then compare answers with another pair and justify any disagreement.

6. 39–45 min · Share and exit check. Teacher presents the final prompts on the plenary and exit prompts and selects two contrasting examples for discussion. Students explain one successful prediction and one lesson learned, then complete the worksheet’s final reflection: draw or describe a net that could make a cube and state how they know.

Resources

• the Nets and Models teaching deck
• the nets and solids investigation worksheet
• the 3D shape nets pack
• Scissors
• Coloured pencils or felt-tip pens
• Glue or tape, if needed
• Pencils and erasers
• Class display screen or interactive whiteboard
• A completed cube or cuboid model for demonstration

Assessment

• Listen to predictions and partner explanations, checking whether students refer to faces, edges, vertices and how faces meet.
• During construction, observe whether students test predictions systematically and can identify why a net fails or succeeds.
• Collect or quickly review the worksheet, looking for a prediction, a tested result, evidence and a clear final explanation.

Differentiation

• Provide pre-cut nets, enlarged nets and nets with clearly marked fold lines for students who find cutting, visual tracking or fine-motor tasks difficult.
• Offer a partially completed worksheet, a vocabulary bank with labelled diagrams, and sentence starters such as “I predicted…”, “My evidence is…” and “This net did not work because…”.
• Pair students thoughtfully and provide guided support by folding one face at a time. Allow students with dyslexia or autism to record explanations orally, point to evidence or use a quiet workspace where appropriate.
• Extend fast finishers by asking them to find or design more than one net for a cube, then prove that each net has the correct number and arrangement of faces.