Chemical and Physical Changes

Overview

This 20-minute lesson is designed for Year 11 students (ages 15-16), in a small group setting of 4 students. It aligns with the National Curriculum for England KS4 Science Programme of Study – specifically the topics on chemistry and physical and chemical changes.

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National Curriculum Links

• Subject Content (Chemistry - Key Stage 4):
  • "Chemical reactions, including the distinction between physical and chemical changes"
  • "The identification of chemical and physical changes based on observable properties."
• Working Scientifically:
  • Make and record observations carefully.
  • Use scientific language and classification.

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Lesson Objectives:

WALT (We Are Learning To):

• Understand and differentiate between chemical and physical changes.
• Identify examples of each type of change using observable properties.
• Describe key characteristics that distinguish chemical changes from physical changes.

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Success Criteria

• I can explain the difference between a physical and a chemical change.
• I can give examples of physical and chemical changes.
• I can identify witnesses of a change (e.g., colour change, gas production, state change).
• I can confidently classify changes seen during the lesson as chemical or physical.

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Resources

• Whiteboard and markers
• Small clear containers (plastic cups)
• Common materials for demonstration (e.g., water, salt, vinegar, baking soda, paper, candle, ice)
• Dyslexia-friendly printed handout with key vocabulary (clear font, coloured background to reduce strain)
• Visual aids: illustrated cards showing changes (e.g., melting chocolate, rusting iron).

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Lesson Structure

Introduction (3 minutes)

• Greet students and introduce the learning objectives (WALT).
• Begin with a short question: "Can you think of ways matter can change? Is every change the same?"
• Briefly explain:
  • Physical Changes: Changes that affect the form or state of a substance but do not make new substances (e.g., melting, dissolving).
  • Chemical Changes: Changes that result in the formation of new substances (e.g., burning, rusting).

Activity 1: Sorting Changes (8 minutes)

• Present 6 illustrated change cards showing phenomena such as melting ice, burning paper, dissolving salt in water, cutting paper, vinegar reacting with baking soda, and condensation.
• Ask students, in pairs, to sort the cards into “Physical change” or “Chemical change.”
• Facilitate group discussion after sorting, encouraging reasons behind choices (observations like gas bubbles, colour change, reversibility).
• Teacher writes key characteristics on the whiteboard in two columns: Physical vs Chemical.

Differentiation:

• Provide dyslexia-friendly key terms sheet (using simple language and colours).
• Use paired work to support students with additional needs.
• Offer sentence starters to help frame explanations, e.g., “This is a chemical change because…”

Extension:

• For advanced learners, introduce challenges such as reversible vs irreversible chemical changes and ask for examples.

Activity 2: Mini Investigations (6 minutes)

• Students perform quick hands-on tests with provided materials:
  • Dissolving salt in water (physical change)
  • Mixing vinegar and baking soda (chemical change with gas production)
• Students note observations using a simple table: Change observed / Physical or Chemical / Reason.
• Discuss group results and reinforce criteria.

Differentiation:

• Provide diagrams showing the reactions and observations for students who need additional support.
• Encourage verbal sharing of observations for less confident writers.

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Plenary (3 minutes)

• Recap key differences and ask each student to give one example of a chemical and physical change from the lesson.
• Use thumbs up/down quick formative assessment: "Does burning paper involve a chemical change?" etc.
• Highlight real-life relevance: pollution, cooking, recycling.

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Assessment and Feedback

• Observational assessment during sorting and mini investigations.
• Use student explanations and reasoning to assess understanding.
• Give immediate feedback and address misconceptions on the spot.

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Additional Notes

• Be mindful to speak clearly and at a moderate pace to support all learners, especially those with processing difficulties.
• Maintain a positive, engaging tone and encourage curiosity to foster a memorable experience.

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This focused, interactive lesson not only meets core KS4 requirements but gives students hands-on and visual engagement with key science concepts, supporting diverse learners and challenging advanced students simultaneously.