Rough or Smooth?

Overview

In this fifth lesson of Materials All Around Us, students investigate the surfaces of everyday materials by touch and careful observation. They build on earlier sorting and describing experiences, using shared scientific vocabulary to compare, classify and explain their choices.

Learning intentions

• WALT explore and compare the surfaces of everyday materials.
• WALT use the words rough, smooth, bumpy and slippery.
• WALT group materials according to a shared surface property.
• WALT explain our thinking using a photograph or voice recording.

Success criteria

• I can safely feel a material and describe its surface.
• I can use rough, smooth, bumpy or slippery to compare materials.
• I can place materials into groups and say why they belong together.
• I can record my observation with a photo, drawing or voice recording.

Curriculum links

• Physical Science — comparing and grouping everyday materials according to shared physical properties.
• Physical Science — observing and describing material properties using simple comparisons.
• Science capabilities — observing, interpreting, communicating and participating safely in an investigation.
• Te Mātaiaho learning competencies — thinking, communicating and managing self.

Lesson structure (45 minutes)

1. 0–5 min · Hook and prediction. Open with the question and mystery-surface slides and reveal two covered objects, such as sandpaper and a polished stone. Students predict which will feel rough or smooth, then share what they notice without touching yet.

2. 5–11 min · Vocabulary and safety. Use the vocabulary and safety slides to introduce rough, smooth, bumpy and slippery, acting out each word with hand movements. Demonstrate one-finger or whole-hand touching, remind students not to put materials near their mouths or eyes, and explain that they must stop if a surface feels sharp, wet, dirty or uncomfortable. Students repeat the words and practise describing a partner’s hand movement.

3. 11–25 min · Surface investigation. Place students in six groups of three, with roles of toucher, recorder and equipment manager; rotate roles after each sample. Give each group a tray containing safe, clean samples such as fabric, cardboard, foil, a wooden block, bubble wrap, a smooth plastic lid, a sponge and a sealed slippery object. Students feel one item at a time, compare it with another, and record or draw their observations on the surface investigation recording sheet. Circulate and ask, “What do you notice?”, “Which word fits best?” and “What could you compare it with?”

4. 25–34 min · Classify and justify. Display four headings from the sorting and discussion slides: rough, smooth, bumpy and slippery. Groups place their samples or sample labels under the heading they think fits best. Students may place one item between two headings if they can explain that it has more than one property. Invite groups to justify a choice using the frame, “We put ___ with ___ because it feels ___.”

5. 34–41 min · Communicate evidence. Model a close-up photo of one sample and a short Seesaw voice recording: “This is bubble wrap. It is bumpy because I can feel the raised bumps.” Pairs choose one material, photograph it safely, and record or dictate a sentence using a target word. Students who cannot access Seesaw tell their sentence to the teacher or make a drawing on the recording and explanation section. Use the Seesaw example and sentence-starter slide as a prompt.

6. 41–45 min · Plenary and assessment. Return to the final comparison and reflection slide and revisit the opening predictions. Students show a hand signal for rough, smooth, bumpy or slippery as the teacher names several familiar objects, then complete an oral exit response: “One material I explored was ___; it was ___ because ___.” Collect worksheets and note students needing further support.

Resources

• Six trays of safe, clean everyday material samples
• Six labelled group workspaces
• Rough or Smooth? slide deck
• Surface investigation recording sheet
• Seesaw-enabled tablet or camera for each pair, where available
• Pencils, crayons and clipboards
• Handwashing supplies or sanitising wipes
• Optional blindfold for teacher demonstration only, not student use

Assessment

• Listen for accurate use of rough, smooth, bumpy and slippery during group investigation; record names of students who confuse or avoid the vocabulary.
• Check whether students classify materials using an observable property and can give a reason rather than simply naming a group.
• Review the worksheet and Seesaw evidence, including the exit response, for a description that links a material to a surface property.

Differentiation

• Provide picture-word cards, real examples, gestures and the sentence frame, “It feels ___ because ___.” Accept pointing, drawing, gesture, dictated answers or a home-language contribution before recasting in English.
• Pre-select large, easy-to-hold samples for students with fine-motor or sensory needs. Offer gloves, a visual choice board, or the option to observe rather than touch; never require contact with an aversive texture.
• Pair students strategically and give clear roles, visual turn-taking prompts and additional adult support for Seesaw recording.
• Extend confident students by asking them to find a material that fits two groups, compare which of two surfaces is more or less rough, or suggest a use that suits a material’s surface.