Earth Systems Intro

Overview

Students begin the unit by investigating Earth’s structure as a system. They model how different geological layers differ in composition and use evidence-based reasoning to connect Earth systems to tectonic activity studied later in the unit.

Learning intentions

• Students will identify Earth’s main geological layers (crust, mantle, outer core, inner core).
• Students will describe how layer properties (composition and behaviour) differ from one another.
• Students will use a scientific model to explain what evidence supports ideas about Earth’s structure.
• Students will practise planning and conducting a short, safe investigation/model check to answer a question.

Success criteria

• I can label Earth’s layers and match each layer to a likely material/behaviour using my model notes.
• I can explain (in my own words) why scientists cannot directly observe Earth’s interior and what evidence they use instead.
• I can describe at least two differences between layers (e.g. composition, temperature, or density).
• I can use scientific vocabulary correctly (e.g. crust, mantle, core, temperature, density, evidence).

Curriculum links

• AC9S8U03 — investigate tectonic activity including formation of geological features at plate boundaries and describe evidence for plate tectonics (as background: Earth structure and forces).
• AC9S8I01 — develop investigable questions, reasoned predictions and hypotheses to explore scientific models (students will pose and test a model explanation).
• AC9S8I02 — plan and conduct reproducible investigations by identifying variables/assumptions and managing risks (students will run a brief model-based investigation with controlled conditions).
• (Unit connection) The lesson establishes Earth systems ideas that support later investigations of tectonic activity and geological evidence.

Lesson structure (30 minutes)

1. 0–5 min · Hook (think–pair–share). Teacher shows a simple diagram of Earth layers and asks: “If we can’t drill to the centre, how do scientists know what’s inside Earth?” Students answer individually, then discuss with a partner.

2. 5–12 min · Direct teaching (Earth structure overview). Teacher explains the four main layers, focusing on what each layer is thought to be made of, and why conditions change with depth (temperature, density). Students complete a guided Earth-layers notes sheet: label, then write one key feature per layer.

3. 12–20 min · Model investigation (evidence reasoning). Teacher provides a “layer cake” model kit: different-coloured discs or clay/plasticine for crust, mantle, outer core, inner core plus a simple temperature/density prompt card (e.g. “denser materials go deeper” and “hotter materials closer to inner core”). Students predict where each model material should sit, then assemble a cut-and-compare model to check whether their ordering matches the teacher’s evidence-based pattern.

4. 20–26 min · Micro inquiry (hypothesis test). Teacher displays an investigable question: “Does increasing depth in Earth models correspond to increasing density and temperature?” Students state a hypothesis, then justify it using their model observations and the evidence idea discussed earlier.

5. 26–30 min · Exit ticket (formative check). Teacher collects an exit ticket: (a) label the layers on a blank diagram, and (b) write one sentence explaining the best piece of evidence scientists use when direct observation is impossible.

Resources

• Guided notes template (one-page Earth layers)
• Layer model materials (e.g. coloured foam discs/clay/plasticine or paper rings)
• Earth layers diagram for teacher use
• Model assembly prompt cards (density/temperature cues)
• Exit ticket slips (diagram + short response)
• Whiteboard/markers
• Timer

Assessment

• Teacher circulates during model assembly, checking students’ layer ordering and use of scientific vocabulary.
• Formative assessment during the micro inquiry: students’ hypothesis and justification.
• Exit ticket: accuracy of layer labels and quality of evidence-based reasoning.

Differentiation

• Support: provide a word bank and sentence starters (e.g. “Scientists use evidence such as… to infer…” “As depth increases, the model suggests that…”).
• Support: give partially completed diagrams for students who need scaffolding.
• Extension: ask advanced students to compare two types of evidence (e.g. seismic waves versus density/temperature inference) and argue which is most persuasive and why.
• EAL/SEN: allow oral responses recorded on the model notes sheet; use visuals and minimal text on cards; pre-teach key terms (crust, mantle, core, density, temperature, evidence).

Extension (optional)

• Not included.