Geography · Year 4 · Volcanoes and Earthquakes · Summer Term

Inside Our Planet

Discover what our Earth is made of by exploring its different layers, from the hot, solid core to the crust we live on.

TL;DR:Take your pupils on an incredible journey to the centre of the Earth! These activities help to peel back the layers of our planet, revealing the hot, dynamic world that exists right beneath our feet.

• National Curriculum Attainment Targets
• The National Curriculum in England: Geography programmes of study: Key Stage 2 - describe and understand key aspects of physical geography, including: volcanoes and earthquakes

About This Topic

This topic introduces Year 4 pupils to the fundamental structure of our planet, a key component of the physical geography strand within the Key Stage 2 National Curriculum for England. By exploring the Earth's layers, from the crust to the inner core, pupils build a foundational understanding that will support later learning about geological processes such as earthquakes, volcanoes, and the formation of mountains. The topic moves from the tangible (the crust we live on) to the abstract (the immense heat and pressure of the core), using models and analogies to make these concepts accessible.

Understanding the composition, state (solid/liquid), and relative scale of the crust, mantle, outer core, and inner core is the primary goal. This knowledge helps contextualise our planet not as a static ball of rock, but as a dynamic system. It explains the 'why' behind many surface-level geographical features and phenomena. This unit provides an excellent opportunity for hands-on, inquiry-based learning that sparks curiosity about the world beneath our feet.

Key Questions

1. Explain the role of each of the Earth's four main layers.
2. Compare the characteristics of the Earth's crust and mantle.
3. Identify the state of matter of the inner and outer core.

Learning Objectives

• Identify and name the four main layers of the Earth: crust, mantle, outer core, and inner core.
• Describe the state of matter (solid or liquid) of each layer.
• Explain that the Earth's layers differ in thickness and temperature.
• Create a simple model to represent the structure of the Earth.
• Explain the role of the crust as the layer we live on and the mantle as a layer of slowly moving rock.

Key Vocabulary

Crust	The thin, outermost layer of the Earth, made of solid rock, which includes the land and the ocean floor.
Mantle	The thickest layer of the Earth, found between the crust and the core, made of hot, semi-solid rock that can flow very slowly.
Outer Core	A layer of molten (liquid) iron and nickel that surrounds the inner core and generates the Earth's magnetic field.
Inner Core	The very centre of the Earth, a solid ball of iron and nickel that is extremely hot but kept solid by immense pressure.
Tectonic Plate	A large, moving section of the Earth's crust and uppermost mantle.

Watch Out for These Misconceptions

Common Misconception

The Earth's crust is very thick.

What to Teach Instead

The crust is the thinnest of all the Earth's layers. It is more like the skin of an apple in comparison to the rest of the fruit.

Common Misconception

The mantle is a sea of liquid lava.

What to Teach Instead

The mantle is mostly solid rock, but it is so hot it can flow very slowly, like treacle. The lava we see from volcanoes comes from small pockets of melted rock in the upper mantle.

Common Misconception

The Earth is hollow inside.

What to Teach Instead

The Earth is completely filled with layers of rock and metal. These layers get denser and hotter the closer you get to the centre.

Common Misconception

The core is just one single part.

What to Teach Instead

The core is made of two distinct parts: a liquid outer core made of molten iron and nickel, and a solid inner core made of the same metals, which is solid due to immense pressure.

Active Learning Ideas

Maker Learning

Play-Dough Planet

Pupils use different colours of play-dough to create a cross-section model of the Earth. They build the planet from the inside out, starting with a small ball for the inner core and adding subsequent layers for the outer core, mantle, and crust.

45 min·Individual

Maker Learning

Hard-Boiled Earth

Use a hard-boiled egg as an analogy for the Earth's structure. The shell represents the thin crust, the egg white is the mantle, and the yolk represents the core. Pupils can carefully crack the shell to simulate tectonic plates.

30 min·Pairs

Maker Learning

Earth's Layers Foldable

Pupils create a foldable paper craft that opens to reveal the four layers of the Earth. On each flap, they can write the name of the layer and a key fact about its composition or state of matter.

50 min·Individual

Real-World Connections

• Understanding the movement of the mantle and crust helps explain why earthquakes and volcanic eruptions occur in certain parts of the world.
• The liquid outer core creates the Earth's magnetic field, which is what makes compasses point north and is vital for navigation.
• Geologists study rock from the crust to find important natural resources like oil, gas, and metals.
• Heat from the Earth's interior, known as geothermal energy, can be used to generate electricity and heat buildings.
• The structure of the ocean floor, part of the crust, is studied to understand marine habitats and underwater landforms like trenches and mid-ocean ridges.

Assessment Ideas

Peer Assessment

Pupils complete a 'label the layers' diagram of the Earth. This can be done individually or in pairs to check for understanding of the names and order of the layers.

Peer Assessment

Pupils create a short non-chronological report or a poster about the Earth's layers, including at least one key fact for each layer.

Quick Check

Pupils use a 'two stars and a wish' format to review their own model of the Earth, identifying two things they did well and one thing they could improve.

Frequently Asked Questions

How do we know what the inside of the Earth is like if we cannot dig there?

Scientists study seismic waves created by earthquakes. The way these waves travel and change direction reveals the different materials and layers they are passing through, much like a medical scan.

Why is the inner core solid when it is the hottest part of the Earth?

The pressure at the centre of the Earth is incredibly high. This intense pressure squeezes the atoms of iron and nickel so tightly together that they cannot melt and are forced to remain a solid.

What does the Earth's core do?

The movement of the liquid outer core creates Earth's magnetic field. This field acts like a shield, protecting our planet from harmful radiation from the sun.