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

1. Which type of weathering is this: water freezing and expanding in cracks? (physical weathering / chemical weathering / biological weathering) → physical weatheringPrompt: Is it caused by temperature and ice, by a chemical reaction, or by living things?
2. What is the difference between weathering and erosion? (Weathering breaks rock down; erosion carries the pieces away / They are exactly the same / Weathering moves rocks to the sea / Erosion only happens in deserts) → Weathering breaks rock down; erosion carries the pieces awayPrompt: One breaks, the other moves.
3. Which type of weathering is this: tree roots growing into cracks? (physical weathering / chemical weathering / biological weathering) → biological weatheringPrompt: Is it caused by temperature and ice, by a chemical reaction, or by living things?

• Pass round different rocks and ask how each one might have formed.
• Share the objective: Physical, chemical and biological weathering. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Which type of weathering is this: water freezes in a crack, expands and splits the rock?
• Step 1: Physical weathering breaks rock into pieces without changing its chemicals.
• Step 2: So the answer is: physical (freeze–thaw, heating and cooling)
• Answer: physical (freeze–thaw, heating and cooling)
• 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. Which type of weathering is this: iron minerals in rock rust and crumble? (physical (freeze–thaw, heating and cooling) / chemical / biological) → chemicalPrompt: Is a living thing involved? Are new substances formed, or does the rock just break into pieces?
2. In which climate is freeze–thaw weathering most common? (in a hot desert that never freezes / in a tropical rainforest / where temperatures often go above and below 0 °C / under the sea) → where temperatures often go above and below 0 °CPrompt: Water must freeze and melt again and again.

• 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. Weathering and erosion: which statement is NOT true? (Plant roots can split rocks. / Weathering helps turn rock into soil. / Erosion and weathering are the same process. / Limestone caves form by chemical weathering.) → Erosion and weathering are the same process.Prompt: What does water do when it freezes?
2. Which type of weathering is this: rainwater, a weak acid, slowly dissolves limestone to form caves? (physical (freeze–thaw, heating and cooling) / chemical / biological) → chemicalPrompt: Is a living thing involved? Are new substances formed, or does the rock just break into pieces?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-6.