Key learning points

1. Earth is a spherical, rocky planet with a thin crust, partially covered in water.
2. Under Earth’s crust is a dense rocky layer, called the mantle.
3. In the centre of Earth is a solid metallic core surrounded by a liquid outer core.
4. Temperature and pressure increases towards the centre of Earth, making the inner core extremely hot and solid.
5. Scientists use models to better understand phenomena, including Earth's structure.

Keywords

• Crust - The rocky, outermost layer of Earth.

• Mantle - A layer of dense rock found below the crust. Parts of it behave as a fluid over very long, geological time scales.

• Outer core - The outer core is a liquid layer of mostly iron and nickel that lies between the mantle and inner core.

• Inner core - The inner core is a solid ball of mostly iron that lies at the centre of Earth, within the outer core.

• Model - Used by scientists to represent parts of the natural world that are difficult to observe or explain directly.

Common misconception