1. Chapter 3 Introducing Earth
Science 8

2. Getting Started… Verb Noun Adjective Destroy To reduce to pieces….
Destruction
The process of reducing to pieces….
Destructive
Tending to cause damage or to reduce to pieces…
Radiate
To release energy….
Radiation
Energy released in the form of rays or waves….
Radiant
Released as waves or rays….

3. Lesson 1: The Earth System (pages 90-95)

4. What are the Main Parts of the Earth System?
A system is a group of parts working together as a whole.
The Earth system involves a constant flow of matter through different parts.
The rock cycle and water cycle are Earth systems.
Water Cycle water evaporates from the ocean and other bodies of water and rises into the atmosphere and then falls from the sky as rain.
Rock Cycle  new rock can form from molten magma, which then rises to the surface and hardens on land; forming new rock.
The constant flow of matter through the Earth is driven by energy.
Sun
Heat Released from Earth

5. Parts of the Earth System
The Earth system has four main spheres: the atmosphere, the hydrosphere, the geosphere, and the biosphere. The sun an be considered part of he Earth system as well as it is a major source of energy.
Atmosphere: outermost layer, mostly gases, thin layer
Geosphere: metal core, solid middle layer, and rocky outer layer.
Hydrosphere: ¾ of Earth is covered with water
Biosphere: contains the living organisms

6. Feedback Within a System
When feedback occurs, a system returns– or feeds back– to itself data about a change in the system.
Feedback can increase the effects of a change, as in the case of warming glaciers or slow the effects down.
This can change the climate (atmosphere), the glaciers (hydrosphere) and the ground (geosphere)

7. How Do Constructive and Destructive Forces Change Earth?
Lands are constantly being created and destroyed by competing forces.
Constructive forces shape the land’s surface by building up mountains and other land masses.
These collisions form landmasses such as mountains.
They are a result of a collision of the lithosphere, the Earth’s top layer. This layer is broken into parts, or plates. Plates move slowly over time. This is where the idea of plate tectonics comes into play!
Earthquakes and volcanoes also take part as constructive forces!

8. Destructive Forces
Ice, wind, rain, and changing temperatures tear the rock of the Earth apart.
This is called weathering, which is a form of erosion.
These break down or destroy landmasses.

9. Lesson 2: Earth’s Interior

10. How Do Geologists Learn About Earth’s Interior?
Processes that are occurring inside of Earth cause changes that occur on the surface, just below the surface or the places where we live.
Geologists have used two man types of evidence to learn about Earth’s interior; direct evidence from rock samples and indirect evidence from seismic waves.
Rock Samples
From drilling
Seismic Waves
Studying paths and the changes they take

11. The three main layers of Earth are the crust, the mantle, and the core
The three main layers of Earth are the crust, the mantle, and the core. These layers vary greatly in size, composition, temperature and pressure.
The deeper down inside Earth the greater the pressure.
The temperature inside Earth increases as depth increases.

12. What are the features of Earth’s crust, mantle and core?
The crust is a layer of solid rock that includes both dry land and the ocean floor.
Main elements: oxygen and silica
Thin layer
Between 5 and 40 kilometers thick
Thickest under mountains
Oceanic Crust  below the ocean  basalt  fine grained and dark.
Continental Crust  forms continents  granite  coarse grained and light in color.

13. The Mantle
The mantle is made of rock that is very hot, but solid. Scientists divide the mantle into layers based on the physical characteristics of those layers. Overall, the mantle is nearly 3,000 kilometers thick.
Lithosphere: the uppermost part of the mantle, brittle, about 100 km thick
Asthenosphere: hotter than the lithosphere, less rigid, solid
Mesosphere: hot and more rigid, stiff because of high pressure

14. The Core
The core is made of mostly the metals iron and nickel. It consists of two parts– a liquid outer core and a solid inner core.
Outer Core: molten (liquid) metal surrounding the inner core.
Inner Core: dense ball of solid metal

15. The Core and Earth’s Magnetic Field
Because Earth has a magnetic field, the planet acts like a giant bar magnet.
When using a compass, the needle aligns with the lines in Earth’s magnetic field.
The needle points to Earth’s magnetic North Pole which is not the same as the geographic North Pole.

16. Lesson 3: Convection and the Mantle