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.
- Complete the word equation: zinc + oxygen → ___ (carbon dioxide / zinc oxide / zinc carbonate / calcium oxide) → zinc oxidePrompt: A metal reacting with oxygen makes a metal oxide.
- Calcium carbonate is heated strongly: calcium carbonate → calcium oxide + ___ (oxygen / water / carbon dioxide / hydrogen) → carbon dioxidePrompt: What is left when you take CaO away from CaCO₃?
- Word equations: which statement is NOT true? (Combustion is a reaction with oxygen. / The arrow in a word equation means "equals". / Thermal decomposition breaks a substance down using heat. / Reactants are written on the left of the arrow.) → 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.
- Complete the word equation: aluminium + oxygen → ? → aluminium oxidePrompt: When a metal reacts with oxygen it forms an oxide.
- Firefighters cut a firebreak (a strip with no trees) in front of a wildfire. Which side of the fire triangle does this remove? (water / oxygen / fuel / heat) → fuelPrompt: What does the fire need to keep spreading?
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.
- Complete the word equation: sodium + oxygen → ? → sodium oxidePrompt: When a metal reacts with oxygen it forms an oxide.
- Why is a gas boiler with a poor air supply dangerous? (It produces too much oxygen / Incomplete combustion produces toxic carbon monoxide / It stops producing heat completely / It makes the water too pure) → Incomplete combustion produces toxic carbon monoxidePrompt: What forms when there is not enough oxygen?
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