Layers of the Earth for Kids: Crust, Mantle & Core

Layers of the Earth for kids: The Earth is made of four main layers — the crust (the thin outer shell we live on), the mantle (a thick layer of hot rock), the outer core (liquid metal), and the inner core (solid metal as hot as the surface of the sun!). If Earth were an egg, the crust would be as thin as the eggshell.

Introduction

We live on the very surface of our planet, but there is a lot going on underneath! If you could dig a hole straight through the Earth, you would travel about 12,742 km and pass through layers that get hotter and denser the deeper you go.

Let's take a journey to the center of the Earth!

The 4 Layers

• Crust: The thin outer layer we live on — 5-70 km thick. It's made of rock and is thinner under oceans than under continents.
• Mantle: The thickest layer at about 2,900 km. Made of hot rock that flows very slowly like thick honey.
• Outer Core: A layer of liquid iron and nickel about 2,200 km thick. Its swirling creates Earth's magnetic field!
• Inner Core: A solid ball of iron and nickel about 1,220 km in radius. It's about 5,500°C — as hot as the surface of the sun!

How Do We Know What's Inside?

Nobody has ever dug to the center of the Earth (the deepest hole ever drilled was only 12.3 km deep!). So how do we know what's down there? Scientists study earthquake waves! When an earthquake happens, waves travel through the Earth, and they behave differently in solids, liquids, and different types of rock.

By measuring how earthquake waves travel, scientists can figure out what each layer is made of, how thick it is, and whether it is solid or liquid. It's like figuring out what's inside a present without unwrapping it!

Try This!

Make an Earth model with a hard-boiled egg! The thin shell is like the crust, the egg white is like the mantle, and the yolk is like the core. Or make one with playdough — roll a ball of red (inner core), wrap it in orange (outer core), then green (mantle), and finally a thin layer of blue and brown (crust)!

Cool Facts

• The crust makes up less than 1% of Earth's total volume
• The mantle makes up about 84% of Earth's volume
• The inner core is solid even though it's incredibly hot — extreme pressure keeps it from melting
• Earth's magnetic field, created by the outer core, protects us from harmful solar radiation
• The temperature increases by about 25-30°C for every kilometer you dig down

Did You Know?

• If Earth were the size of an apple, the crust would be thinner than the apple's skin!
• The deepest hole ever drilled (Kola Superdeep Borehole in Russia) only reached 12.3 km — not even through the crust!
• Earth's inner core is growing by about 1 mm per year as the outer core slowly solidifies

Wrap Up

Even though we can't see them, Earth's layers are responsible for everything from earthquakes and volcanoes to the magnetic field that protects us from space radiation. Our planet is like a giant, layered machine that has been running for 4.5 billion years!