EARTH’S LAYERSNotes

EARTH’S LAYERS The Earth can be divided into different layers

based on either composition or based on their different physical properties.

Density and temperature both increase for deeper layers of the Earth.

EARTH’S COMPOSITIONAL LAYERSComposition: what something is made of

THE CRUST The crust is the outermost, thinnest, least

dense layer. Continental crust is made mostly of the rock

granite and is thicker and less dense than oceanic crust.

Oceanic crust is made mostly of the rock basalt.

Overall, crustal rocks are rich in the elements silicon (Si) and oxygen (O).

MANTLE The mantle is the hot, middle, thickest layer

and accounts for most of the Earth's bulk. It is denser than the crust, but not as dense

as the core. The density of the mantle increases with

depth due to increasing pressure. Mantle rocks are richer in iron (Fe) and

magnesium (Mg) than crustal rocks. Diamonds form in the high pressure

conditions of the mantle.

THE CORE The core lies at Earth's center. The core is

made mostly of iron and nickel, and it is the hottest, densest layer.

EARTH’S PHYSICAL LAYERS

LITHOSPHERE The lithosphere is the cold, brittle layer at

Earth's surface. It is a solid layer that contains all of the crust

and a very thin part of the mantle's top. Overall, the lithosphere is a stiff, rigid layer

that is broken into large pieces called tectonic plates.

These plates move around on top of the less rigid layer below them.

OUTER CORE The outer core is the liquid, outer portion of

the Earth's core. The slow, gradual flow in the outer core

produces the Earth's magnetic field.

INNER CORE The inner core is the solid, inner portion of

the Earth's core.

EARTH’S FORMATION

HOW DID EARTH FORM? About 4.6 billion years ago. Materials from a large cloud of gas and dust

formed together. This was because of GRAVITY!

GRAVITY? Gravity: The force that every object exerts on

all other objects because of its mass. The closer the objects, the more gravity. The bigger (or more mass) the more gravity. Those dust and gas particles… well, they

began to gravitate, and create planets. The larger the objects, the more pull.

EARTH’S LAYERS FORMED Because of DENSITY! The more dense something is, the more it will

sink. All of the materials that made up the Earth in

it’s early years were “sorted” by their densities.

Most dense (Heaviest) to the bottom. That is why the core is iron!!!

MAGNETOSPHERE

EARTH’S MAGNETIC FIELD The inner core spins

faster than the outer core

This produces streams of flowing, molten iron in the outer core.

This creates magnetism from the iron flowing.

Over time, the magnetism can change!

MAGNETOSPHERE – WHAT IS THAT? Protects us from cosmic rays and charged

particles from the sun.

THE END