• 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. Which can carry rock fragments away (erosion)? (nothing moves rocks / rivers, wind and glaciers / only plants / only sunlight) → rivers, wind and glaciersPrompt: What moves sand and stones from place to place?
3. Which type of weathering is this: iron in rock rusting? (physical weathering / chemical weathering / biological weathering) → chemical 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: Weathering, erosion or deposition?. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Which process is this: tree roots growing into a rock?
• Step 1: Weathering breaks rock into smaller pieces where it is.
• Step 2: So the answer is: weathering (rock breaks down in place)
• Answer: weathering (rock breaks down in place)
• 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 process is this: wind blowing soil off a dry field? (weathering (rock breaks down in place) / erosion (pieces are carried away) / deposition (pieces are dropped)) → erosion (pieces are carried away)Prompt: Breaking, moving or dropping?
2. Three of these are examples of deposition. Which one is NOT? (waves dragging pebbles off a beach / a river dropping mud at its mouth to make a delta / sand piling up into a dune / pebbles settling at the bottom of a lake) → waves dragging pebbles off a beachPrompt: Is the rock being broken, carried, or dropped?

• 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. Three of these are examples of weathering. Which one is NOT? (a boulder cracking after many hot days and cold nights / tree roots growing into a rock / water freezing in a crack and splitting a rock / sand piling up into a dune) → sand piling up into a dunePrompt: Is the rock being broken, carried, or dropped?
2. Why do roads get more potholes after a cold winter? (Cold makes the road melt. / Water seeps into cracks, freezes, expands and breaks the surface. / Snow eats the road. / Cars are heavier in winter.) → Water seeps into cracks, freezes, expands and breaks the surface.Prompt: What happens to water's size when it freezes?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-4.