• Quick retrieval from earlier learning (How fossils form and what they reveal). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Footprints and burrows preserved in rock are called… (minerals / trace fossils / crystals / body fossils) → trace fossilsPrompt: They show the traces of activity, not the body itself.
2. Fossils: which statement is NOT true? (Most living things that ever lived did not become fossils. / Fossils in deeper rock layers are usually older. / Fossils form in a few years. / Fossils show that many species have become extinct.) → Fossils form in a few years.Prompt: Did people ever meet a living T. rex?
3. Why do we have very few fossils of jellyfish? (Jellyfish never existed in the past / They have no hard parts, so they usually rot before being preserved / They live on land / They are too big) → They have no hard parts, so they usually rot before being preservedPrompt: Most fossils are bones, shells or teeth.

• Pass round different rocks and ask how each one might have formed.
• Share the objective: Use rock layers to put events in order. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Undisturbed rock layers, listed from the bottom up: D, C, E. Which layer is the youngest?
• Step 1: In undisturbed layers, the lowest is oldest and the highest is youngest.
• Step 2: So the answer is: E
• Answer: E
• 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. Undisturbed rock layers, listed from the bottom up: D, C, A, E. Which layer is the oldest? (A / D / E / C) → DPrompt: Sediment settles on top of what is already there.
2. There is a gap in the rock record where some layers have been worn away before new layers formed on top. What is this called? (a fossil / an unconformity / a fault / a dyke) → an unconformityPrompt: It marks missing time.

• 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. Undisturbed rock layers, listed from the bottom up: E, C, B. Which layer is the youngest? (B / C / E) → BPrompt: Sediment settles on top of what is already there.
2. Rock layers are found tilted and folded. What does this tell you? (They formed on the Moon / They were laid down tilted / Forces moved the rock after the layers formed / They are igneous rock) → Forces moved the rock after the layers formedPrompt: Sediment settles in flat, horizontal layers.

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