Earth’s radius is about 6,371 kilometres. The mantle reaches to roughly 2,900 kilometres below the surface. The liquid outer core extends to about 5,150 kilometres depth, below which the solid inner core begins. The crust is much thinner and varies greatly in thickness between different places.
Earth and geology · Discover & try
What is inside Earth?
Reading level 3 of 5 · IndependentChange
Word help
Mantle
The thick layer of mostly solid rock below the crust.
Outer core
Earth’s liquid, metal-rich layer surrounding the inner core.
Depth
Distance below the surface, distinct from distance from the centre.
Watch · Try · Explain
See how it works
The interactive activity is loading.
Approximate radial boundaries; crust thickness varies and its thin edge is highlighted for visibility.
What to look for
- Compare depth with radius.
- Look for the liquid layer.
- Notice how thin the crust is.
Explain what you noticed
A diagram colours the mantle red. Does that prove it is a global liquid magma ocean?
Keep this idea: Earth’s mantle is mostly solid rock; the outer core is liquid and the inner core solid.
Follow the sources
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
You’ve reached the end of this journey
Choose another journey →