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Science lesson plan · 7th grade (Year 8 in England) · 45 minutes

Combustion, oxidation and the fire triangle

Chemical reactions, acids and bases

CCSS NGSS.MS-PS1-2England: KS3 Chemistry: Chemical reactions

Objective and success criteria

Students will: Combustion, oxidation and the fire triangle.

  • 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: Reactants, products and word equations

Leads to: the next skill in this area.

Materials: Teacher demo or video, Indicator color chart, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (Reactants, products and word equations). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Complete the word equation: copper + oxygen → ___ (copper chloride / copper carbonate / carbon dioxide / copper oxide) → copper oxidePrompt: A metal reacting with oxygen makes a metal oxide.
  2. What is needed for fuels to burn? (water and light / oxygen and enough heat / carbon dioxide / nitrogen only) → oxygen and enough heatPrompt: Think of the fire triangle: fuel, heat and…
  3. Word equations: which statement is NOT true? (The arrow in a word equation means "equals". / Combustion is a reaction with oxygen. / Incomplete combustion can produce carbon monoxide, a poisonous gas. / Thermal decomposition breaks a substance down using heat.) → The arrow in a word equation means "equals".Prompt: Which side of the arrow is which?

Hook · 5 min

  • Drop an antacid tablet in water (or show a clip) and ask whether a new substance is being made.
  • Share the objective: Combustion, oxidation and the fire triangle. 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: Complete the word equation: calcium + oxygen → ?
  • Step 1: metal + oxygen → metal oxide
  • Step 2: So the answer is: calcium oxide
  • Answer: calcium oxide
  • 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. Complete the word equation: magnesium + oxygen → ? → magnesium oxidePrompt: When a metal reacts with oxygen it forms an oxide.
  2. Why is a gas boiler with a poor air supply dangerous? (It makes the water too pure / Incomplete combustion produces toxic carbon monoxide / It produces too much oxygen / It stops producing heat completely) → Incomplete combustion produces toxic carbon monoxidePrompt: What forms when there is not enough oxygen?

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. Combustion: which statement is NOT true? (Burning fossil fuels releases carbon dioxide. / Hydrogen burns to make only water. / Combustion is a reaction with oxygen that releases energy. / Combustion is an endothermic reaction.) → Combustion is an endothermic reaction.Prompt: Is energy taken in or given out when something burns?
  2. What are the products when methane (natural gas) burns completely? (oxygen and hydrogen / carbon monoxide and soot / methane and oxygen / carbon dioxide and water) → carbon dioxide and waterPrompt: Methane contains carbon and hydrogen.

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: Reactants, products and word equations.
  • Use concrete materials: teacher demo or video.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • 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-7.

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

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Combustion, oxidation and the fire triangle

Name

Date

Score/ 8

  1. Question 1

    A fire blanket is thrown over a burning pan. Which side of the fire triangle does it remove?

    • A. oxygen
    • B. none
    • C. fuel
    • D. heat
  2. Question 2

    Complete the word equation: magnesium + oxygen → ?

    Answer

  3. Question 3

    Combustion: which statement is NOT true?

    • A. Rusting is a slow oxidation reaction.
    • B. Hydrogen burns to make only water.
    • C. Burning fossil fuels releases carbon dioxide.
    • D. Water is the best way to put out an oil fire in a pan.
  4. Question 4

    Firefighters cut a firebreak (a strip with no trees) in front of a wildfire. Which side of the fire triangle does this remove?

    • A. fuel
    • B. water
    • C. heat
    • D. oxygen
  5. Question 5

    Complete the word equation: calcium + oxygen → ?

    Answer

  6. Question 6

    Complete the word equation: aluminium + oxygen → ?

    Answer

  7. Question 7

    Complete the word equation: sodium + oxygen → ?

    Answer

  8. Question 8

    What are the products when methane (natural gas) burns completely?

    • A. methane and oxygen
    • B. carbon monoxide and soot
    • C. carbon dioxide and water
    • D. oxygen and hydrogen

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Answer key: Combustion, oxidation and the fire triangle

  1. 1. A. oxygen

  2. 2. magnesium oxide

  3. 3. D. Water is the best way to put out an oil fire in a pan.

  4. 4. A. fuel

  5. 5. calcium oxide

  6. 6. aluminium oxide

  7. 7. sodium oxide

  8. 8. C. carbon dioxide and water