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Science

Inside the Earth

Overview

Students explore the structure of the Earth, discovering what lies beneath the surface and how scientists know what is there.

Learning Objective
Students describe the four layers of the Earth and understand what evidence tells us about the Earth's interior.

Resources needed

  • A piece of fruit with a stone such as mango or avocado as a model
  • OR a hard-boiled egg

Lesson stages

0 / 7 done
  1. 1 Ask: has anyone ever dug to the centre of the Earth? (No — it is too hot and deep).
  2. 2 Ask: how do scientists know what is inside if nobody has been there?
  3. 3 Introduce seismic waves: vibrations from earthquakes travel through the Earth and their speed tells us about the layers.
  4. 4 Show the fruit or egg as a model: skin = crust, flesh = mantle, stone = core.
  5. 5 Describe each layer: crust (thin, solid, we live on it), mantle (thick, semi-molten rock), outer core (liquid iron), inner core (solid iron, extremely hot).
  6. 6 Ask: why is the inner core solid even though it is hotter than the outer core? (enormous pressure).
  7. 7 Discuss volcanoes: magma from the mantle reaches the surface.

Tap a step to mark it as done.

Variations

  • Research and draw the Earth's layers to scale — the crust would be paper-thin.
  • Discuss tectonic plates — the crust is broken into large moving sections.
  • Connect to earthquakes: where do they happen and why?
More information

Teach: crust, mantle, core, layer, seismic, pressure, magma, lava. The fruit model makes the abstract concept immediately visual and tactile.

Focus on three layers — crust, mantle, core — before distinguishing inner and outer core.

Can students name and describe the four layers of the Earth? Can they explain one piece of evidence that tells us about the Earth's interior?

Any layered fruit works as a model. Draw the cross-section in soil. No specialist equipment needed.

Students often think lava comes from the centre of the Earth. It actually comes from the upper mantle — the core is far too deep for magma to reach the surface directly.

Earth's internal structure is one of the most remarkable discoveries in science — entirely inferred from seismic data without any direct observation. This teaches the power of indirect scientific evidence.

Activity details
Primary Medium 20–25 minutes no prep Whole Class, Small Group Indoor & Outdoor
Topics
Earth Structure Geology Earth Science