• Quick retrieval from earlier learning (Physical and chemical changes). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Is this a physical or a chemical change: iron rusting? (physical change / chemical change) → chemical changePrompt: Is a new substance made?
2. A nail left outside turns orange-brown and flaky. What has happened? (The nail melted / The nail dissolved / Paint fell on it / Iron reacted with oxygen and water to make rust) → Iron reacted with oxygen and water to make rustPrompt: Rusting needs both air and water.
3. Physical and chemical changes: which statement is NOT true? (Melting is a chemical change. / In a chemical reaction, atoms are rearranged to make new substances. / Burning is a chemical change. / Rusting needs both oxygen and water.) → Melting is a chemical change.Prompt: Does each change make a new substance?

• Drop an antacid tablet in water (or show a clip) and ask whether a new substance is being made.
• Share the objective: Reactants, products and word equations. Read the success criteria together.

• 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: calcium + oxygen → calcium 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.

• 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: zinc + oxygen → ___ (zinc oxide / carbon dioxide / zinc carbonate / calcium oxide) → zinc oxidePrompt: A metal reacting with oxygen makes a metal oxide.
2. Calcium carbonate is heated strongly: calcium carbonate → calcium oxide + ___ (water / carbon dioxide / oxygen / hydrogen) → carbon dioxidePrompt: What is left when you take CaO away from CaCO₃?

• 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.

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

1. In the reaction "iron + sulfur → iron sulfide", what are the reactants? (sulfur and iron sulfide / iron and sulfur / iron sulfide / iron only) → iron and sulfurPrompt: Reactants are on the left of the arrow.
2. Word equations: which statement is NOT true? (Combustion is a reaction with oxygen. / Thermal decomposition breaks a substance down using heat. / Products are the substances you start with. / Reactants are written on the left of the arrow.) → Products are the substances you start with.Prompt: Which side of the arrow is which?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-7.