Video Transcript
Which layer of Earth is in a liquid
state? (A) The crust, (B) the mantle, (C)
the outer core, (D) the inner core, (E) the lithosphere.
Earth’s internal structure is made
up of four main layers: the crust, the mantle, the outer core, and the inner
core. This question focuses on which of
these layers are in a liquid state. So let’s take a closer look at the
physical states of each layer.
The crust is the thinnest
layer. It is composed of solid rock and is
rigid and hard. The mantle, found below the crust,
is the thickest internal layer of Earth. The uppermost part of the mantle is
solid rock. The crust and the uppermost part of
the mantle form the lithosphere, the solid outer part of Earth. Below the lithosphere is the
asthenosphere and the lower mantle, which are composed of partially molten rock. Below the mantle is the Earth’s
core, which can be split into the outer and inner core.
The core is found at the center of
the planet, where temperatures and pressures are at their highest. The outer core is composed of iron
and nickel, which are in the liquid state due to the extremely high
temperatures. The inner core is subjected to
higher pressures than the outer core. So although the inner core is also
composed of iron and nickel, these metals are in the solid state.
From this information, we now know
that the layer of Earth that is in a liquid state is the outer core.
