Misconceptions in Mixtures

Overview

This lesson (13 of 18) builds on prior learning about solutions and mixtures by targeting common errors in understanding about separating mixtures, dissolving, and identifying solutions. Students will identify misconceptions, apply correct ideas using examples, and correct statements in a multiple-choice worksheet.

Learning intentions

• WALT identify common misconceptions about mixtures and solutions.
• WALT explain why each misconception is incorrect using observable properties and particle-based ideas (at a Year 7 level).
• WALT correctly match examples (e.g. salt water, muddy water, air) to whether they are mixtures or solutions.

Success criteria

• I can correctly address three given misconceptions from the worksheet.
• I can choose the correct option for each misconception and justify my choice using a clear science reason.
• I can describe how a substance’s properties affect how it mixes or separates.

Success criteria for each lesson step is embedded below as “Check for understanding” and the exit task.

Curriculum links

• SC4-SOL-01 — Students explain how the properties of substances enable separation in a range of techniques.
• SCLS-SOL-01 — Students describe the properties of familiar substances and materials.
• Students use safe, structured thinking about observations and explanations relevant to solutions and mixtures (Stage 4).

Lesson structure (30 minutes)

1. 0–4 min · Hook (misconception quick-check). Teacher shows 3 short scenario cards (mixed) and reads them aloud; students select A/B/C on mini-whiteboards. Students answer: “Is it a solution?” “Is it a mixture?” “Can separation by filtration be used easily?” (teacher collects without discussing yet).

2. 4–10 min · Modelled clarification (teacher examples). Teacher explicitly models correcting misconceptions using 3 “Stop–Fix–Think” examples:

• Misconception 1: “If something dissolves, it is no longer a mixture.” Teacher models: dissolving forms a solution, which is still a mixture because substances are still present but uniformly mixed.
• Misconception 2: “Filtration can separate a solution.” Teacher models: filtration separates insoluble solids from liquids; dissolved substances need different methods (e.g. evaporation/crystallisation).
• Misconception 3: “All mixtures look uniform, so they are solutions.” Teacher models: uniform appearance helps, but “solution” depends on dissolving and uniform mixing; not all uniform-looking samples are solutions (e.g. air is a mixture). Students complete a 3-item “thumbs” check: thumbs up only for the corrected statement.

3. 10–15 min · Guided discussion (why misconceptions happen). Teacher leads a structured discussion using sentence starters on the board:

• “I used to think ___ because ___. Now I think ___ because ___.” Students pair-share for 2 minutes, then one or two pairs report; teacher records common reasoning errors (e.g. relying on appearance only, confusing dissolving with “gone”, mixing up separation methods).

4. 15–25 min · Independent worksheet (multiple choice correction). Teacher gives the worksheet “Correct the Misconceptions (3 options)” with 3 misconceptions, each with 4 multiple-choice answers:

• Students circle the correct correction.
• Students add a short reason in one sentence frame: “It is incorrect because ___.” Autistic support: worksheet includes visual icons (✘ misconception / ✓ correction), limited text per item, and predictable layout. Teacher circulates, using a quick checklist: chosen option matches the correction, and reason mentions particle/uniform mixing or appropriate separation method.

5. 25–28 min · Video clip debrief (YouTube). Teacher plays the YouTube clip titled “Common Science Misconceptions” for the remaining time (or a teacher-selected segment if the clip is long), pausing at 2–3 key misconceptions. Students hold up a card: “Same as ours / Different from ours,” then explain one difference in one sentence.

6. 28–30 min · Exit ticket (success criteria check). Students answer 3 multiple-choice questions (one per misconception) on a short slip. Teacher collects slips to confirm mastery of the three misconceptions.

Resources

• Scenario cards (3) for the hook (print or slides shown with large text)
• Mini-whiteboards or A/B/C response cards
• Slide deck (teacher examples): “Stop–Fix–Think” with three misconceptions
• Worksheet: “Correct the Misconceptions” (multiple choice, icon support, sentence frames)
• Sentence starters displayed on board
• YouTube “Common Science Misconceptions” clip (prepared to play without searching during class)
• Teacher checklist for misconceptions during circulation

Assessment

• Formative: mini-whiteboard A/B/C responses in the hook (identify starting misconceptions).
• Formative: thumbs check during modelled clarification and student answers in the guided discussion.
• Summative within lesson: worksheet multiple-choice selections plus one sentence reason; short exit ticket of 3 questions.

Differentiation

• Provide sentence starters and an example model on the worksheet for students who need structure (e.g. “It is incorrect because filtration separates insoluble solids, not dissolved substances.”).
• Reduce reading load: fewer words per question, use icons, and allow students to point to answers before writing.
• For students needing extension: ask them to add one “separation method clue” (e.g. “If it’s a dissolved solid, think evaporation/crystallisation instead of filtration.”).
• For EAL/support needs: allow responses using short phrases first, then one complete sentence using the provided frame.