• 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. Fossils of tropical ferns have been found in Antarctica. What is the best explanation? (Antarctica has always been tropical / Antarctica was once in a warmer location, before plate movement carried it south / Ferns grow in ice today / The fossils were carried there by penguins) → Antarctica was once in a warmer location, before plate movement carried it southPrompt: Continents move slowly over millions of years.
2. Fossils: which statement is NOT true? (Fossils form in a few years. / Fossils show that many species have become extinct. / Most living things that ever lived did not become fossils. / Insects can be preserved in amber (fossilised tree resin).) → Fossils form in a few years.Prompt: Did people ever meet a living T. rex?
3. Why are fossils usually found in sedimentary rock, not igneous rock? (Igneous rock is too young / Animals never lived near volcanoes / Igneous rock forms from molten rock that would destroy remains / Sedimentary rock is magnetic) → Igneous rock forms from molten rock that would destroy remainsPrompt: Think about the temperature of magma.

• 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: B, E, A, D, C. Which layer is the youngest? (C / A / B / E) → CPrompt: 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 dyke / a fossil / a fault / an unconformity) → 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: A, B, E, C, D. Which layer is the youngest? (A / D / C / E) → DPrompt: Sediment settles on top of what is already there.
2. The same unusual fossil is found in a layer in Spain and a layer in Morocco. What does this suggest? (The layers are different ages / The layers are on the same continent / The fossil travelled by boat / The two layers formed at about the same time) → The two layers formed at about the same timePrompt: Index fossils lived for a short time but were widespread.

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