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GCSEChemistryWJECRevision Notes1. Chemical Substances, Reactions & Essential Resources1.4 The Ever-Changing EarthStructure of the Earth

Structure of the Earth (WJEC GCSE Chemistry): Revision Note

Exam code: 3410

Richard Boole

Last updated

WJEC ChemistryWJEC Science (Double Award): Chemistry

Structure of the Earth

  • The structure of the Earth consists of four main layers:

    • Inner core

    • Outer core

    • Mantle 

    • Crust

Structure of the Earth Diagram

Structure of the Earth

The Earth consists of the inner core, outer core, mantle and crust

Composition of the Earth

Layer

Thickness (km)

Composition

Inner core

1400

A solid and dense layer composed of iron and nickel at around 5500 °C

Outer core 

2100

A liquid layer composed of iron and nickel at about 5000 - 5500 °C

Mantle

2900

A layer of semi-molten rock which is less dense than the outer core

Crust

Variable

A layer of solid rock which is less dense than the mantle

  • The thickness of the crust ranges from 5 to 70 km thick, with an average thickness of 20 km

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Richard Boole

Author: Richard Boole

Expertise: Chemistry Content Creator

Richard has taught Chemistry for over 15 years as well as working as a science tutor, examiner, content creator and author. He wasn’t the greatest at exams and only discovered how to revise in his final year at university. That knowledge made him want to help students learn how to revise, challenge them to think about what they actually know and hopefully succeed; so here he is, happily, at SME.