Sorting Materials

Overview

In this final lesson of the unit, students classify materials using their properties, then justify their choices by separating what they observed from what they inferred. They finish by writing a Claim, Evidence, Reasoning (CER) paragraph using scientific vocabulary.

Learning intentions

• Students will distinguish between observations (what we directly measure or observe) and inferences (what we conclude using evidence).
• Students will classify materials based on observable properties such as texture, colour, dissolving, melting, magnetism, and conductivity.
• Students will use scientific vocabulary to explain and justify their classification decisions using CER.

Success criteria

• I can sort materials into categories using clear property-based criteria.
• I can label statements as observations or inferences with examples from our task.
• I can write a CER paragraph where the claim matches the evidence and the reasoning links the evidence to scientific ideas.

Curriculum links

• Science: Using evidence and scientific thinking to explain observations and patterns.
• Science: Classifying and describing materials using physical properties.
• Key competencies: Thinking (making sense of information), Managing self (staying on task), Participating and contributing (collaborating in group roles).
• Literacy in science: Communicating ideas clearly using subject-specific language.

Lesson structure (90 minutes)

1. 0–10 min: Activate prior learning Students recall what they did in Lessons 1–2 (properties and testing). Teacher shares a short scenario: “A student says the spoon ‘must be metal because it is shiny’.” Students discuss whether this is an observation or inference and why.

2. 10–25 min: Observation vs inference mini-check In pairs, students sort a small set of teacher-provided sentence cards into two columns: observation or inference. As a class, teacher records “observation stems” (e.g., “I measured…”, “I noticed…”) and “inference stems” (e.g., “Therefore…”, “This suggests…”).

3. 25–55 min: Classification challenge (group sorting) Groups of 3–4 students receive a tray of materials (e.g., paper, foil, plastic, chalk, sand, salt, sugar, cooking oil, iron filings or a small magnet, and a safe dissolving set where appropriate). They:

• Test properties (only planned tests: dissolving in water, magnet attraction, melt/heat response if safe and supervised, and simple conductivity using a basic setup if available).
• Record evidence in a table: property → result.
• Sort materials into categories agreed by the group (e.g., “dissolves vs does not dissolve”, “magnetic vs not magnetic”, “rough vs smooth”, “conducts vs doesn’t conduct”). Teacher circulates using prompts: “What did you observe? What did you infer? What property is your category based on?”

4. 55–65 min: Observation–inference card debrief Each group selects 3 of their recorded results and creates two sentences for each: one observation and one inference. Groups trade with another group to check accuracy using teacher success criteria (does the inference clearly follow from evidence?).

5. 65–80 min: Write CER paragraph (individual) Students write a CER paragraph answering: “How did you classify these materials, and what evidence supports your classification?” Required structure:

• Claim: states the classification rule(s) clearly (e.g., “Materials that dissolve in water belong together…”).
• Evidence: lists measured/observed results (not feelings or guesses).
• Reasoning: explains why the evidence supports the claim using scientific vocabulary (e.g., “dissolving shows a property of forming a solution”, “magnetism indicates magnetic materials”).

6. 80–90 min: Quick conference and exit ticket Students complete an exit ticket: “One observation from today was… One inference I can make from it is…” Teacher collects for feedback (or quick scan of one class set).

Resources

• Materials for testing: assorted solids (sand, salt, sugar, chalk, paper, foil, plastic pieces, iron filings or a magnet, cooking oil) and water for dissolving trials
• Safe testing tools: trays, labels, droppers/spoons, paper towels
• Simple magnet test equipment (magnets, iron filings if available)
• Basic conductivity equipment if school-approved and safe (or an alternative teacher-led “conducts heat/electricity” demonstration)
• Recording sheets with a properties/results table
• Sentence cards for observation vs inference sorting
• CER writing template (optional) and word bank (observation, measured, noticed, result, suggests, therefore, property, classify, dissolve, magnetic, conductivity, texture)

Assessment

• Observation vs inference sorting accuracy (paired activity and debrief).
• CER paragraph quality: claim linked to categories, evidence drawn from recorded results, reasoning using scientific language and evidence-based logic.
• Exit ticket identifies whether students can correctly produce observation and inference examples from today’s work.

Differentiation

• Support: provide sentence starters for observation/inference and a partially completed properties/results table; allow students to use a checklist for CER structure.
• Support (SEN): reduce the number of categories to two clear classification rules; offer a word bank with key verbs (measured, observed, dissolved, attracted).
• Extension: ask students to compare two possible classification schemes and explain which is more scientifically useful because it is based on reliable properties.
• EAL: allow sentence cards with visuals; encourage students to rehearse their CER aloud with a partner before writing; accept bilingual planning notes before final English paragraph.