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Science lesson plan · 5th grade (Year 6 in England) · 45 minutes

Reversible and irreversible changes

Materials and their properties

CCSS NGSS.2-PS1-4CCSS NGSS.5-PS1-4England: KS2 Y5 Properties and changes of materials

Objective and success criteria

Students will: Reversible and irreversible changes.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Dissolving and solutions

Leads to: Conservation of mass

Materials: A tray of everyday objects, Sorting hoops, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (Dissolving and solutions). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Is jelly crystals soluble or insoluble in water? (soluble (dissolves in water) / insoluble (does not dissolve)) → soluble (dissolves in water)Prompt: Imagine stirring it into a glass of water. Would it disappear from view?
  2. 5 g of sugar is dissolved in 150 g of water. What is the mass of the solution, in g? → 155 gPrompt: When something dissolves, does it disappear or is it still there?
  3. Which change makes sugar dissolve faster? (using bigger sugar lumps / using warmer water and stirring / using colder water / leaving it still) → using warmer water and stirringPrompt: Particles move faster when they are warmer.

Hook · 5 min

  • Pass round objects made of different materials and ask why each one was chosen.
  • Share the objective: Reversible and irreversible changes. Read the success criteria together.

I do: model it · 10 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: Is this change reversible or irreversible: melting butter?
  • Step 1: A reversible change can be undone, like melting, freezing, dissolving and evaporating.
  • Step 2: So the answer is: reversible
  • Answer: reversible
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 10 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. Is this change reversible or irreversible: mixing vinegar and bicarbonate of soda (baking soda)? (reversible / irreversible) → irreversiblePrompt: Could you get the starting material back?
  2. Which change is reversible? (mixing vinegar and bicarbonate of soda (baking soda) / freezing water into ice / cooking an egg / baking a cake) → freezing water into icePrompt: Changes of state and dissolving can be reversed.

You do: independent practice · 10 min

  • Students work on the student sheet. Circulate and check the first two answers of every student early.
  • Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

Exit ticket · 5 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. Which change is reversible? (baking a cake / burning wood / an iron nail rusting / freezing water into ice) → freezing water into icePrompt: Changes of state and dissolving can be reversed.
  2. Why is burning a candle wick irreversible? (Nothing new is made / It can be turned back into a wick by cooling / The wick only melts / New substances such as carbon dioxide and ash form) → New substances such as carbon dioxide and ash formPrompt: What is left after burning?

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: Dissolving and solutions.
  • Use concrete materials: a tray of everyday objects.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Move on to: Conservation of mass.
  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-5.

Free lesson plan from eurekami.com/lesson-plan-builder

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Reversible and irreversible changes

Name

Date

Score/ 8

  1. Question 1

    How could you get salt back after dissolving it in water?

    • A. filter it
    • B. burn it
    • C. freeze it
    • D. evaporate the water

  2. Question 2

    Is this change reversible or irreversible: baking a cake?

    • A. reversible
    • B. irreversible

  3. Question 3

    Which change is reversible?

    • A. an iron nail rusting
    • B. toasting bread
    • C. burning wood
    • D. dissolving salt in water

  4. Question 4

    Which is a sign that a new material has been made?

    • A. bubbles of gas are given off when two substances mix
    • B. ice changes to water
    • C. a puddle dries up
    • D. sugar disappears in tea

  5. Question 5

    Is this change reversible or irreversible: melting chocolate?

    • A. reversible
    • B. irreversible

  6. Question 6

    Which change is irreversible?

    • A. boiling water into steam
    • B. melting butter
    • C. melting chocolate
    • D. toasting bread

  7. Question 7

    Why is burning a candle wick irreversible?

    • A. The wick only melts
    • B. It can be turned back into a wick by cooling
    • C. New substances such as carbon dioxide and ash form
    • D. Nothing new is made

  8. Question 8

    Is this change reversible or irreversible: cooking an egg?

    • A. reversible
    • B. irreversible

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Answer key: Reversible and irreversible changes

  1. 1. D. evaporate the water

  2. 2. B. irreversible

  3. 3. D. dissolving salt in water

  4. 4. A. bubbles of gas are given off when two substances mix

  5. 5. A. reversible

  6. 6. D. toasting bread

  7. 7. C. New substances such as carbon dioxide and ash form

  8. 8. B. irreversible