Earth's Three Layers Quiz

10 Questions

What are the three main layers of the Earth's rocky portion?

Crust, Mantle, Core

Which layer of the Earth is a semi-solid magma layer consisting of iron, magnesium, and silicon?

Mantle

Why is it difficult to answer the question of how many layers make up the Earth?

The Earth's layers have multiple sub-layers

What causes the movement of tectonic plates?

Convection currents in the mantle

What is the average thickness of a tectonic plate?

60 miles

What are seismologists primarily concerned with studying?

Earthquakes

Which scientific principle causes the different layers of the Earth?

Gravity

Which layer of the Earth is the hottest and densest?

The lower mantle

At what approximate depth does the central mantle, also known as the transition zone, extend to?

400 miles below the surface

What is the primary composition of the Earth's core?

Iron and nickel

Study Notes

The Earth is composed of both rocky layers and atmospheric layers, with the focus of this lesson being on the rocky layers.
The Earth's core consists of a solid inner core and a liquid outer core, both made primarily of iron and nickel.
The inner core is extremely hot (over 9000°F) and under immense pressure (up to 3.6 million atmospheres), keeping it in a solid state.
The outer core is liquid, with a thickness of about 2000 miles and an approximate temperature of high heat.
The mantle is the largest layer of the Earth, making up about 84% of its total volume and starting about 20 miles below the surface.
The mantle is semi-solid, with flowing molten magma and is divided into three layers: the asthenosphere, central mantle, and lower mantle.
The asthenosphere is the uppermost layer of the mantle proper, extending from 60 miles below the Earth's surface to about 400 miles down. It is characterized by convection-like currents that push hot molten magma towards the crust, causing volcanic activity and earthquakes.
The central mantle, also known as the transition zone, is the layer where rocks undergo a transformation from their surface structures to a denser form. It extends from 250 miles to 410 miles below the surface and holds as much water in the form of hydroxide as all the Earth's oceans.
The lower mantle is the hottest and densest layer of the mantle, starting about 410 miles below the surface and extending down to the Earth's core. It is more solid than the other mantle layers due to the increased pressure at its depth.