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

1. Is this rock permeable or impermeable: marble? (permeable (lets water through) / impermeable (does not let water through)) → impermeable (does not let water through)Prompt: Does water soak in, or run off the surface?
2. What is soil made from? (only sand / tiny pieces of rock mixed with dead plant and animal material, air and water / melted rock / only dead leaves) → tiny pieces of rock mixed with dead plant and animal material, air and waterPrompt: Soil forms slowly from broken-down rock.
3. Rocks and soils: which statement is NOT true? (Rocks can be compared by hardness and permeability. / Some rocks let water soak through them. / Rocks can be natural or made by people, like brick and concrete. / Soil is only made of dead leaves.) → Soil is only made of dead leaves.Prompt: What is soil mainly made of?

• Pass round different rocks and ask how each one might have formed.
• Share the objective: How fossils form. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: In how a sea shell becomes a fossil, what happens straight after "the sediment slowly turns into rock"?
• Step 1: a sea creature dies → its shell sinks to the sea floor → layers of sediment cover it → the sediment slowly turns into rock → the fossil is found in the rock millions of years later
• Step 2: So the answer is: the fossil is found in the rock millions of years later
• Answer: the fossil is found in the rock millions of years later
• 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. In how a sea shell becomes a fossil, what happens straight after "layers of sediment cover it"? (the fossil is found in the rock millions of years later / the sediment slowly turns into rock / its shell sinks to the sea floor / a sea creature dies) → the sediment slowly turns into rockPrompt: Fossils form very slowly, buried in rock.
2. A fossil is found in a deep rock layer. Another is found in a layer near the top. Which is probably older? (it is impossible to say anything / the fossil near the top / they are the same age / the fossil in the deeper layer) → the fossil in the deeper layerPrompt: Layers build up one on top of another.

• 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. Why do most fossils show bones, teeth and shells rather than skin? (Scientists remove the skin / Hard parts last longer; soft parts rot quickly / Skin turns into rock straight away / Animals had no skin) → Hard parts last longer; soft parts rot quicklyPrompt: Which parts of an animal rot first?
2. In how a fossil forms, what happens straight after "minerals slowly replace the bones over millions of years"? (an animal dies / the soft parts rot away / the rock is worn away and the fossil is uncovered / it is quickly buried by mud or sand) → the rock is worn away and the fossil is uncoveredPrompt: Only the hard parts usually become fossils.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-3.