What's Inside the Earth? Layers of the Earth Quiz
Play the quiz
What's Inside the Earth? Layers of the Earth Quiz
About this quiz
Layers of the Earth quiz: what's inside our planet? 25 questions about the crust, mantle and core. 🌋
How hot is Earth's core? How deep have we ever dug? How long would it take to fall straight through the planet? Dig deep into the science beneath your feet. Great for family quiz nights, road trips and classrooms.
❓ IN THIS QUIZ
- Which layer of Earth is liquid?
- How deep is the deepest hole ever drilled?
- What creates Earth's magnetic field?
- If you jumped into a tunnel straight through the Earth, how long would the fall take?
💬 How many did you get right? Tell us your score in the comments. What would you expect to find at the center of the Earth?
How to play
- Read the question and look at the pictures.
- Pick your answer before the timer runs out (or switch the timer off).
- See if you were right and read the fun fact.
Answers and fun facts (spoilers!)
- Let's dig deep! How many main layers does the Earth have?
4
Crust, mantle, outer core and inner core! - Which layer of Earth is the thinnest?
Crust
If Earth were an apple, the crust would be about as thin as the skin! - Which layer is the thickest?
Mantle
The mantle is about 2,900 km (1,800 miles) thick! - Which layer is liquid?
Outer core
The outer core is a sea of liquid iron and nickel! - Why is the super-hot inner core solid?
Huge pressure
The weight of the whole planet squeezes the iron so hard it stays solid! - What creates Earth's magnetic field?
Moving liquid iron
Swirling liquid iron in the outer core works like a giant dynamo! - About how far is it to the center of the Earth?
About 6,400 km
Earth's radius is about 6,371 km (3,959 miles). - Where is Earth's crust thinnest?
Under oceans
Ocean crust is only about 5 to 10 km thick. Under mountains it can be many times thicker! - How deep is the deepest hole ever drilled?
About 12 km
Russia's Kola Superdeep Borehole reached 12,262 m (40,230 ft), not even through the crust! - About how hot is Earth's inner core?
About 5,400 °C
That's about as hot as the surface of the Sun! - What is the mantle made of?
Hot, slow-flowing rock
Mantle rock is solid, but over millions of years it slowly flows like thick toffee! - What do we call melted rock underground?
Magma
It's called magma underground, and lava once it erupts! - Earth's tectonic plates slide over which layer?
The mantle
The plates ride on the soft, hot upper mantle. - How fast do tectonic plates move?
Like nails grow
Plates move a few centimeters a year, about as fast as your fingernails grow! - What was the giant supercontinent of long ago called?
Pangaea
Pangaea broke apart about 200 million years ago. - Who first proposed that continents drift around?
Alfred Wegener
Wegener noticed the continents fit together like puzzle pieces! - What is the boundary between the crust and mantle called?
The Moho
It's short for the Mohorovičić discontinuity. Try saying that fast! - The core is made mostly of which metals?
Iron and nickel
Iron and nickel, the same metals found in many meteorites! - How do scientists study the inside of the Earth?
Earthquake waves
Earthquake waves bend and bounce off the layers, revealing what's inside! - How deep is the world's deepest mine?
About 4 km
South Africa's Mponeng gold mine goes about 4 km (2.5 miles) down! - What happens to the temperature as you go deeper underground?
It gets hotter
Rock gets roughly 25 °C hotter for every kilometer down! - What heats the water in hot springs and geysers?
Hot rock below
Iceland uses this underground heat to warm homes and make electricity! - Earth's inner core is a ball about as wide as what?
70% of the Moon
The inner core is about 2,440 km wide, roughly 70% of the Moon's width! - Which layer do we live on?
Crust
Everything you've ever seen sits on the thin crust! - Final question! If you jumped into a tunnel straight through the Earth, about how long would the fall take?
About 40 minutes
Scientists calculate the fall would take about 38 to 42 minutes!