• Quick retrieval from earlier learning (Decomposers and recycling nutrients; Energy transfer and pyramids). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. What do decomposers do? (pollinate flowers / make food from sunlight / break down dead plants and animals / hunt living animals) → break down dead plants and animalsPrompt: What happens to a fallen leaf over a few months?
2. Producers in a field capture 20000 kJ of energy. About 10% of the energy passes to each next level. How much energy reaches the secondary consumers, in kJ? → 200 kJPrompt: 10% means divide by 10 at each step.
3. Is a bracket fungus on a dead log a producer, a consumer or a decomposer? (producer / consumer / decomposer) → decomposerPrompt: Does it make food, eat living things, or break down dead things?

• Show a food web and ask what would happen if one animal disappeared.
• Share the objective: The carbon cycle. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Does this process remove carbon dioxide from the air or add it: decomposition by microorganisms?
• Step 1: Respiration, combustion and decomposition release carbon dioxide.
• Step 2: So the answer is: adds CO₂ to the air
• Answer: adds CO₂ to the air
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Does this process remove carbon dioxide from the air or add it: decomposition by microorganisms? (removes CO₂ from the air / adds CO₂ to the air) → adds CO₂ to the airPrompt: Which process do green plants use to make glucose?
2. How did fossil fuels such as coal form? (from the remains of ancient plants buried and compressed over millions of years / from melted rock / from volcanoes erupting last century / from seawater evaporating) → from the remains of ancient plants buried and compressed over millions of yearsPrompt: Coal contains carbon that plants once took from the air.

• 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 6 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Which process removes carbon dioxide from the air? (carbon dioxide dissolving in the sea / respiration / burning fossil fuels / volcanic eruptions) → carbon dioxide dissolving in the seaPrompt: Which processes use up carbon dioxide, and which make it?
2. What role do microorganisms play in the carbon cycle? (They decompose dead organisms, releasing carbon dioxide by respiration / They have no role / They photosynthesise in the dark / They turn carbon into oxygen) → They decompose dead organisms, releasing carbon dioxide by respirationPrompt: Decomposers respire too.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-9.