What are Earth's main layers from the outside in?

Crust, mantle, outer core, inner core

What is the boundary between crust and mantle called?

The Mohorovičić discontinuity (Moho)

How do scientists learn about Earth's interior?

By studying seismic waves from earthquakes

Earth's Layers Quiz: 10 Questions That Test What You Know

This Earth's layers quiz covers the crust, mantle, outer and inner core, the Moho boundary, how seismic waves reveal the planet's interior and why the core is so hot. Ten questions test how much you really know about what lies beneath our feet.

Start Earth's Layers Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Layers
What are Earth's main layers from the outside in?
Thin
Which layer is the thinnest?
Thick
Which layer makes up most of Earth's volume?
Liquid
Which layer is liquid?
Inner
Why is the inner core solid despite its heat?
Heat
About how hot is Earth's inner core?
Moho
What is the boundary between crust and mantle called?
Evidence
How do scientists learn about Earth's interior?
Lehmann
Who discovered Earth's solid inner core in 1936?
Deepest
How deep is the deepest hole ever drilled?

Explanations: answer key for all 10 questions

Q1: What are Earth's main layers from the outside in?
Answer: Crust, mantle, outer core, inner core
Each layer has different properties.
Q2: Which layer is the thinnest?
Answer: Crust
It is like the skin of an apple compared to the whole Earth.
Q3: Which layer makes up most of Earth's volume?
Answer: Mantle
It is about 2,900 kilometers thick.
Q4: Which layer is liquid?
Answer: Outer core
Its swirling iron creates Earth's magnetic field.
Q5: Why is the inner core solid despite its heat?
Answer: Enormous pressure
It is mostly iron and nickel.
Q6: About how hot is Earth's inner core?
Answer: About 5,000 to 6,000 °C
That is similar to the Sun's surface.
Q7: What is the boundary between crust and mantle called?
Answer: The Mohorovičić discontinuity (Moho)
Andrija Mohorovičić found it in 1909.
Q8: How do scientists learn about Earth's interior?
Answer: By studying seismic waves from earthquakes
Waves change speed in different layers.
Q9: Who discovered Earth's solid inner core in 1936?
Answer: Inge Lehmann
She was a Danish seismologist.
Q10: How deep is the deepest hole ever drilled?
Answer: About 12 kilometers
The Kola Superdeep Borehole barely scratched the crust.

Earth'S Layers Quiz – Journey to the Center

Earth is made of layers, like an onion. The thin rocky crust floats on the thick mantle, which surrounds a liquid outer core and a solid inner core. Continental crust is up to about 70 kilometers thick, while ocean crust is often only 5 to 10 kilometers.

No one has drilled far beneath the crust, so scientists study the interior using seismic waves from earthquakes. These waves bend, speed up or slow down as they pass through different materials. In 1936, Danish seismologist Inge Lehmann used them to discover the solid inner core.

Heat from Earth's interior drives plate tectonics, volcanoes and earthquakes. The liquid iron outer core generates the magnetic field that protects life from harmful solar radiation. Studying Earth's layers helps us understand how our planet formed and keeps changing.

What This Quiz Teaches

This quiz is for students learning Earth's structure.

What the main layers are
Which layer is thickest
Which layer is liquid
How scientists study the interior
Who discovered the inner core

Did You Know?

The mantle flows very slowly like hot plastic.
Earth's radius is about 6,371 km.
The inner core may spin slightly differently from the mantle.
Diamonds form in the mantle.
Iron makes up about a third of Earth's mass.