Our Essential Question : 6.E.2.1 “What’s Inside the Earth?”

composed rock The earth is composed primarily of rock.

surface covered ¾ or 75% of the earth’s surface is covered by a relatively thin layer of water (some of it frozen).

The entire planet is surrounded by a relatively thin layer of gas we call the atmosphere.

Our Essential Question : Inside “What’s Inside the Earth?”

Classifying the Layers There are two ways to classify the layers of the Earth: Compositional (Chemical): classifies based on chemical properties (ie: elements) Physical: classifies based on physical properties (ie: state of matter)

Classifying the Layers We will focus on the compositional layers.

How do ‘they’ know? If scientists have no way to “dig” even past the crust, then how do they know what is in the center of the Earth? How can they know what the inside of the Earth is made of, if they have never seen it?

We can not see the inside of the Earth, but we can study it using other senses. The most important thing we use to sense the Earth’s core are seismic waves. Seismic waves are waves of energy caused by earthquakes.

Scientists are able to measure these waves as they pass through the Earth. As these waves encounter different materials, they change in important ways, becoming longer, shorter, faster, or slower. Geologists study these changes in the waves, and are able to draw conclusions about what the core of the Earth must look like.

These clues lead geologists to believe that the Earth is made of four distinct layers: crust mantle outer core inner core

THE CRUST

hard crust. The whole earth is made of rocks & minerals. Inside the earth there is a liquid core of molten rock and on the outside there is a hard crust. THE CRUST

The crust is made up of rocks and minerals. Much of the crust is covered by water, sand, soil and ice. If you dig deep enough, you will always hit rock. THE CRUST

Below the loose layer of soil, sand & crumbled rocks found on Earth is bedrock, which is a solid rock. THE CRUST

The outermost layer of the Earth is the CRUST. THE CRUST

The crust is km thick. It is the thinnest layer of the Earth. THE CRUST

The crust is the least dense layer. THE CRUST

The Crust makes up less than 1% of the Earth’s mass (0.4%) THE CRUST

The Crust makes up less than 1% of the Earth’s mass (0.4%) THE CRUST

It is made of oxygen, magnesium, aluminum, silicon, calcium, sodium, potassium, iron. There are 8 elements that make up 99% of the Earth’s crust. THE CRUST

At its outer edge, where it meets the atmosphere, the temperature of the crust of the Earth is the same temperature as the air. So, it might be as hot as 35 °C in the desert and below freezing in Antarctica. But if you dig down, the temperatures go up. Once you reach the mantle – the next layer of the Earth – the temperatures have risen to 400 °C (752°F). THE CRUST

The deepest mine in the world is the TauTona gold mine in South Africa, measuring 3.9 km deep. This is only about 10% of the depth of the crust in Africa, and yet the temperatures down at the bottom of the mine reach a sweltering 55 °C. The mine needs air conditioning to bring the temperature down to the point that it’s comfortable for miners to work all day. THE CRUST

2 types Continental Oceanic thicker thinner km thick5-7 km thick less densemore dense mostly oldyoung THE CRUST

The crust consists of many continental and oceanic plates that have slowly moved and changed positions on the globe throughout geological time.

THE MANTLE

The layer of the Earth between the crust and the core is the MANTLE. THE MANTLE

The mantle is much thicker than the crust, and contains most of the Earth’s mass. The mantle is the Earth’s thickest layer (about 3,000 km deep) THE MANTLE

The Mantle makes up 66% of the Earth’s mass and 83% of the Earth’s volume THE MANTLE

The Mantle makes up 66% of the Earth’s mass and 83% of the Earth’s volume THE MANTLE

It is made up of dense, hot molten rock – (mainly iron & magnesium) which flows. THE MANTLE

Molten “melted by heat” The mantle is molten rock.

The mantle is denser than the crust, but not as dense as the core. THE MANTLE

Temperatures in the mantle range from 600 to 1200 degrees Celsius. THE MANTLE

The crust floats on the mantle. THE MANTLE

A convection current takes place in the mantle. This causes pieces of the crust to move. THE MANTLE

The mantle also has layers. THE MANTLE

The first 50 miles are hard rock. THE MANTLE’s Layers

The next 150 miles are super-heated molten rock that is so hot it can flow under pressure, like tar or peanut butter. THE MANTLE’s Layers

Underneath this heated layer is several hundred miles of solid rock. THE MANTLE’s Layers

Think of the mantle like a peanut butter sandwich. You have the two pieces of bread and the peanut butter between them. In the mantle, we have two layers of solid rock with heated flowing rock between them. THE MANTLE’s Layers

The mantle surrounds the entire dense, metallic core THE MANTLE

The layer of the Earth that extends from below the mantle to the center of the Earth is the CORE, made up of two regions: Outer Core Inner Core THE CORE

THE OUTER CORE

Below the mantle lies the liquid outer core- which is about 2200 km thick. THE OUTER CORE

The outer core is made up of liquid iron and nickel. THE OUTER CORE

The outer core is molten metal. THE OUTER CORE

The outer core is denser than the crust and mantle, but not as dense as the inner core. THE OUTER CORE

Temperatures in the outer core can reach 4000 degrees Celsius. THE OUTER CORE

THE INNER CORE

At the center of the earth is the solid inner core- which is about 1200 km thick. THE INNER CORE

Under great pressure, the inner core is made up of solid iron and nickel. THE INNER CORE

The inner core is the densest layer of the earth. THE INNER CORE

Temperatures in the inner core can reach 5000 degrees Celsius! That’s as hot as the surface of the sun! THE INNER CORE

Even though the temperatures are very high, the great pressure, causes the nickel and iron to solidify. THE INNER CORE

The weight of the whole world, literally, is pressing down on the inner core. All of this pressure, causes the inner core to be forced to a solid state. THE INNER CORE

The solid inner core is surrounded by the liquid (molten) outer core. INNER CORE

The inner core, in combination with the rotation of the Earth, around the outer core creates a dynamo effect where a force field is generated. INNER CORE

This force field is also known as Earth’s magnetic field. INNER CORE

Look at the food choices below. Which do you think would be the best choice to use as a model of the Earth and its layers? State 3 reasons why you decided on your food choice. Also state 1 draw-back of your choice. JOURNAL WORK