Earth Layers Fact Cards
Lithosphere
0-100 km deep
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The outermost layer of the Earth, including the crust and the upper mantle.
Hard, rigid, brittle, and solid, except for the ocean.
Low temperature and low pressure.
Broken into tectonic plates that float on the asthenosphere.
Consists of oceanic and continental lithosphere (oceanic is more dense).
Earthquakes occur in the lithosphere when tectonic plates collide.
Fun facts: The word ‘lithosphere’ is from the Greek lithos meaning ‘rocky’
and sphaira for ‘sphere.’
Asthenosphere & Upper Mantle
100-200 km (Asthenosphere) and 200-700 km (Upper Mantle)
• The layers of the Earth just below the lithosphere; in combination with the lower mantle,
this is the largest layer (about 2/3 of Earth’s mass).
• Asthenosphere is plastic-like viscous rock; more solid closer to core.
• High temperature and pressure: 500-900°C (932-1652°F) at the boundary with the crust;
over 4000°C (7230°F) at the boundary with the core.
• Convection currents in asthenosphere carry heat to the lithosphere and are responsible for
movement of tectonic plates.
Fun facts: The word ‘asthenosphere’ is from the Greek asthenes meaning ‘weak.’
Lower Mantle
700-2900 km
• The layer of the Earth just above the outer core; in combination with the upper mantle, this
is the largest layer (about 2/3 of Earth’s mass).
• Hot, dense rock; becomes more solid closer to core.
• High temperature and pressure: pressure is almost 21 million pounds per square inch (psi)
compared to the pressure at the surface of the Earth which is only 14.7psi; over 4000°C
(7230°F) at the boundary with the core.
Fun facts: Incredibly high pressure exists in the lower layers of the Earth due to the cumulative
weight of all the layers above.
Earth Layers Fact Cards
Outer Core
2900-5200 km
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The layer of the Earth just above the inner core.
A shell of liquid metal, mostly iron and nickel.
High temperature and pressure: 4400°C (7230°F) to 6400°C.
The Earth’s magnetic field is thought to be caused by the fluid movement in this metallic
outer core in contrast to the solid inner core. As the Earth spins, the outer core also spins,
but the solid inner core stays still.
Fun facts: The Sun’s solar wind would blast away our atmosphere, making Earth lifeless,
if not for our protective magnetic field which reaches thousands of kilometers beyond the
surface of the Earth.
Inner Core
5200-6400 km
• The innermost layer of the Earth; 70% of the moon’s radius.
• A solid sphere, mostly iron and nickel.
• Pressure is over 51 million pounds per square inch (psi) compared to the pressure at the
surface of the Earth, which is only 14.7 psi.
• Temperature is 8000°C to 10000°C.
• Even though the inner core has incredible temperatures, the rock does not melt due to
having such high pressure.
• The inner core turns once every 120 years.
Fun facts: The inner core has temperatures as hot as the Sun’s surface! That is enough heat to make
200 cups of coffee per hour for every person on Earth.