1. Chapter 3: The Dynamic Earth
Environmental Science Class
Mrs. Toner

2. Essential Question for this Lesson
How is the Earth a system of interacting components?
Georgia Performance Standards:
- SCSh.7a – The universe is a vast single system in which the basic principles are the same everywhere.
- SEV.1a - Interpret biogeochemical cycles including hydrologic, nitrogen, phosphorus, oxygen and carbon cycles.
- SEV.1d – Relate the cycling of matter and the flow of energy to the Laws of Conservation and Energy.
- SEV.2.a – Describe how the abiotic components (water, air, and energy) affect the biosphere.

3. Section 1: The Geosphere

4. The Geosphere (cont.)
What are the conditions that allow us to survive on a constantly changing planet?

5. Earth as a System
The Earth consists of four parts that all interact with each other:
Rock (Geosphere)
Air (Atmosphere)
Water (Hydrosphere)
Living Things (Biosphere)

6. Earth as a System: The Geosphere
The solid part of the Earth that consists of all rock, as well as the soil and loose rocks on Earth’s surface is the geosphere.
Most of the geosphere is located in Earth’s interior.
At the equator, the average distance through the center of the Earth to the other side is 12,756 km.

7. The Geosphere

8. Earth as a System (cont.)
The atmosphere is the mixture of gasses that makes up the air we breathe.
Nearly all of these gases are found in the first 30 km above the Earth’s surface.

9. Earth as a System (cont.)
The hydrosphere makes up all of the water on or near Earth’s surface.
Much of this water is in the oceans.
Water is also found in the atmosphere, on land, and in the soil.

10. Hydrosphere

11. Earth as a System (cont.)
The biosphere is made up of parts of the atmosphere, the geosphere, and the hydrosphere. It is where life exists.
The biosphere is a thin layer at Earth’s surface that extends from about 9km above the Earth’s surface down to the bottom of the ocean.

12. Earth’s Interior
The Earth is made up of three different compositional layers:
Crust (least dense)
Earth’s thinnest outer layer, makes up less than 1% of Earth’s mass.
Mantle (medium density)
Layer beneath the crust, makes up 64% of Earth’s mass.
Core (most dense)
Earth’s innermost layer,
Made up of hot nickel and iron at the center of the Earth

13. Structure of the Earth
If we consider the physical properties of each layer of Earth, then Earth can be divided into five physical layers:
Lithosphere – Earth’s outer layer
Includes the crust and uppermost part of the mantle
It is a cool, rigid layer
Km thick
It is divided into huge pieces called tectonic plates.
Asthenosphere – Layer beneath the lithosphere
A plastic , solid layer of the mantle made of rock that flows very slowly to allow the tectonic plates to move on top of it.
Physical Properties = the state of matter, its appearance, how it behaves.

14. Structure of Earth (continued)
Mesosphere
Beneath the asthenosphere
The lowest part of the mantle
Outer Core
A dense liquid layer
Inner Core
Dense, solid
Iron and nickel
HOT – 4,000 to 5,000 degrees Celsius!
It is solid because it is under enormous pressure

15. Compositional Layers
Physical Layers

16. Annenberg Media: Earth Revealed Video

17. Activity – work individually
On plain white paper
Horizontal orientation
Divide the paper into two sections
On the left side - draw, label and color the compositional layers of Earth.
On the right side – draw, label, and color the physical layers of Earth.
List three facts for each layer.
Use page 65 in the text as a reference.
Worth 35 points!

18. Plate Tectonics
The lithosphere is divided into pieces called tectonic plates.
These plates glide across the underlying asthenosphere.
The continents are located on tectonic plates.
Major plates:
Pacific Plate
North American Plate
South American Plate
African Plate
Eurasian Plate
Antarctic Plate
Tectonic plates on the Earth's crust move, causing geological phenomena such as earthquakes and volcanoes.

19. Tectonic Plate Map

20. Plate Tectonic Animations

21. Plate Boundaries
Plate boundaries are the boundaries between tectonic plates.
Divergent Boundaries - plates move away from one another (seafloor spreading)
Convergent Boundaries - plates collide into one another (mountains, volcanoes, earthquakes)
Transform Boundaries - plates slip past one another (earthquakes like the ones in California at the San Andreas Fault)

22. SECTION 2: THE ATMOSPHERE
Chapter 3, Pages 71-76

23. Section 2: The Atmosphere
Earth is surrounded by a mixture of gases known as the atmosphere.
Nitrogen (N2)
Oxygen (O2)
Carbon Dioxide (C02)
Earth’s atmosphere changes constantly as these gases are added and removed.
As animals and humans breathe in, oxygen is removed from the atmosphere. As animals and humans breathe out, carbon dioxide is added.
Plants absorb carbon dioxide from the atmosphere and release oxygen into the atmosphere during photosynthesis.
Guided Reading Notes accompany the next 10 slides.

24. Atmospheric Gas Exchange Example
Earth’s atmosphere changes constantly as gases are added and removed.
For example, animals (and humans) breathe in oxygen and exhale carbon dioxide (CO2).
Plants absorb CO2 and release oxygen (O2).
Burning fossil fuels for energy causes CO2 to be released into the atmosphere, too.

25. The Atmosphere (Cont.) The atmosphere also insulates Earth’s surface.
It keeps Earth at temperatures at which living things can survive.
Sunlight penetrates the atmosphere:
A small amount of heat is absorbed by Earth’s surface.
A larger amount of heat is reflected by the clouds back out into space.
Thanks to carbon dioxide and water vapor in our atmosphere, the atmosphere is able to absorb some of the heat emitted by the sun
so we stay warm enough to be able to survive on Earth.

26. Composition of the Atmosphere
1. Nitrogen = 78% of the atmosphere
It enters the atmosphere when volcanoes erupt, and when dead plants and animals decay.
2. Oxygen = 21%
Is primarily produced by plants.
3. Other Gases = 1%
Methane
Carbon dioxide
Argon
Water vapor

27. Air Pressure
Earth’s atmosphere is pulled towards Earth’s surface by gravity.
As a result of gravity, the atmosphere is denser at Earth’s surface.
The air becomes less dense as elevation increases, so breathing at higher elevations is more difficult.

28. Layers of the Atmosphere
1. The Troposphere :
Extends to about 18 Km (10 miles) above Earth’s surface
It’s where we live and where weather occurs.
Densest layer of atmosphere
Temperature decreases as altitude increases in the troposphere.

30. 2. The Stratosphere Above the troposphere
Extends Km (or miles) above Earth’s surface)
Where airplanes fly
Where ozone layer is
Temperature increases as altitude increases because ozone in the stratosphere absorbs the Sun’s UV energy and warms the air.
Ozone is a molecule made up of three oxygen atoms. Almost all the ozone in the atmosphere is concentrated in the ozone layer in the stratosphere. Ozone reduces the amount of UV radiation that reaches Earth. UV radiation can harm humans and other organisms.

31. 3. The Mesosphere The layer above the stratosphere.
Extends to an altitude of about 80 Km (48 miles).
The coldest layer of the atmosphere (- 60 to degrees Celsius).

32. 4. The Thermosphere Atmospheric layer farthest from Earth’s surface.
The air is very thin in this layer so it is the least dense of all the layers.
Nitrogen and oxygen atoms absorb x-rays and gamma rays emitted from the Sun making them electrically charged. This causes the Northern Lights over the North and South Poles.

33. The Northern Lights

34. More Northern Lights

35. CBS Video: “To the Edge of Earth and Back”

36. Energy in the Atmosphere
Energy from the Sun is transferred in Earth’s atmosphere by three mechanisms:
1. Radiation
2. Convection
3. Conduction

37. 1. Radiation
Radiation is the transfer of energy across space and in the atmosphere.
When you stand before a fire, the heat you feel has reached you by radiation.
See diagram on next slide.

38. About ½ of the solar energy that enters the atmosphere passes through and reaches Earth’s surface.
The rest is either absorbed or reflected by Earth’s surface, or is reflected by the clouds.

39. 2. Conduction
Conduction is the flow of heat from a warmer object to a colder object when the objects are placed in direct physical contact.
Like when you touch the handle of a hot pot.

40. 3. Convection Convection is the transfer of heat by air currents.
Hot air rises and cold air sinks.
If you were to hold your hand above a hot iron, you would feel the heat because a current of hot air rises up to your hand.
See diagram on next slide.

42. Energy Transfer Interactive

43. The Greenhouse Effect
Is the process in which gases trap heat near the Earth.
1. Sunlight that penetrates Earth’s atmosphere heats the surface of the Earth.
2. Earth’s surface radiates heat back to the atmosphere where some of the heat escapes back into space.
3. The remainder of the heat is absorbed by greenhouse gases (carbon dioxide and water vapor), which warms the air and the surface of the Earth.