Nets and Structures

Overview

Lesson 12 of 15 in Shapes, Space and Reasoning. Learners investigate which two-dimensional nets fold to make intended three-dimensional objects, using prediction, construction, testing and explanation. The lesson is designed for five Year 4–6 learners and uses visual sequencing, hands-on discovery and written or signed explanations.

Learning intentions

• WALT investigate which nets fold to make a 3D object.
• WALT predict, test and compare nets for cubes and rectangular prisms.
• WALT explain why a net is successful or unsuccessful.
• WALT use mathematical language to describe faces, edges, vertices and shapes.

Success criteria

• I can predict whether a net will form the intended object.
• I can carefully cut, fold or assemble a net and test my prediction.
• I can record successful and unsuccessful examples.
• I can explain my reasoning using faces, edges, matching sides and gaps or overlaps.

Curriculum links

• Geometry: identify, describe and construct two-dimensional shapes and three-dimensional objects.
• Spatial reasoning: visualise, manipulate and communicate how shapes fit together and change position.
• Measurement and geometry processes: use mathematical equipment accurately and record observations.
• Mathematical practices and competencies: problem solving, communicating mathematical ideas, using representations and justifying thinking.

Lesson structure (60 minutes)

1. 0–7 minutes – Engage and revisit Open with the hook and learning intention slides. Show a picture or model of a cube alongside a flat arrangement of squares and ask: “How can a flat net become a solid object?” Briefly revisit face, edge, vertex, net, fold and overlap. Learners may respond by speaking, writing, drawing or signing. Point to each term visually as it is used.

2. 7–15 minutes – Model prediction and testing Display a simple cube net using the net demonstration slides. Think aloud: “I predict this will work because it has six square faces, and each face can fold without covering another face.” Demonstrate checking the number and arrangement of faces, then folding along marked lines. Model recording a prediction, result and reason on the net investigation recording sheet. Emphasise that a wrong prediction is useful mathematical evidence.

3. 15–32 minutes – Investigate nets in pairs Give learners a small selection of pre-drawn cube and rectangular-prism nets, scissors, tape and physical models. For each net, learners first predict, then cut and fold or assemble it. They record “successful” or “unsuccessful” and explain why on the net investigation recording sheet. With five learners, work as two pairs and one individual investigator, rotating roles: predictor, builder and recorder. Use the investigation steps to keep the sequence visible: predict, check, construct, test, record, explain.

4. 32–45 minutes – Compare and reason Bring the class together with the examples. Display one successful and one unsuccessful net using the comparison and discussion slides. Ask:

• How many faces does the object need?
• Which faces meet when folded?
• Where is the gap, overlap or misplaced face?
• Could the net be rearranged to make it work?

Learners compare explanations and improve their own recorded reasoning. Encourage precise statements such as, “This net has six squares, but two faces overlap when folded.”

5. 45–55 minutes – Design challenge Learners design or assemble another valid net for a cube or rectangular prism. They may draw directly onto grid paper or rearrange square or rectangular faces. Test the design and record the result on the design challenge section. Invite learners to make more than one valid cube net if ready. Ask them to explain how their second net is different while still allowing all faces to meet correctly.

6. 55–60 minutes – Reflect and share Revisit the success criteria using the plenary and reflection slides. Each learner shares, writes or signs one completed sentence: “My net worked/did not work because…” Finish with the success criteria template as a brief reflection routine. Collect the worksheets and note one next step for each learner.

Resources

• the Nets and Structures lesson deck
• the net investigation recording sheet
• Pre-drawn cube and rectangular-prism nets, including successful and unsuccessful examples
• Card or lightweight paper
• Child-safe or adaptive scissors
• Glue sticks or removable tape
• Rulers, pencils and coloured pens
• Physical cubes and rectangular prisms
• A teacher-made completed cube net for modelling
• Grid paper for the design challenge

Assessment

• Observe whether each learner predicts before constructing and uses faces, edges, vertices, gaps or overlaps in their explanation.
• Check the worksheet for recorded predictions, test results and reasons, including whether the explanation matches the construction.
• During the plenary, listen for or read written/signed evidence that learners can connect the arrangement of faces with the final 3D object.

Differentiation

• Provide pre-drawn nets, larger templates, adaptive scissors, physical models and clearly marked fold lines. Allow learners to assemble rather than cut where needed.
• Use a visual prediction checklist: “How many faces? Are they the right shapes? Where will they join? Will any overlap?”
• For EAL, deaf learners and learners needing additional language support, use labelled diagrams, gesture, visual sequencing, teacher modelling and sentence frames such as “I predict ___ because ___.” Accept written, drawn or signed explanations.
• For extension, ask learners to design more than one valid net for a cube or rectangular prism, classify which arrangements work, and justify why a near-miss fails.