1. CHAPTER 1 Introduction to Planet “Earth” Instructor: C. Charles Dong

2. Personal Card Name E-mail Classes taking this semester
Science/Math Background
Future Major/Career
Expectation of Class
Expected Grade/Goal

3. Oceanography Geological Oceanography Chemical Oceanography
Physical Oceanography
Biological Oceanography

4. Outline General Information: earth, oceans Scientific Methods
Origin of Earth, Ocean, Atmosphere
Internal Structure of Earth

5. Overview 70.8% Earth covered by ocean
Interconnected global or world ocean
Oceans contain 97.2% of surface water
Fig. 1.3ab

6. The four principal oceans
Pacific
Atlantic
Indian
Arctic
Plus:
Southern or Antarctic Ocean

7. Comparison of elevation and depth
Average depth 3729 m (12,234 ft)
Average elevation 840 m (2756 ft)
Deepest ocean Mariana Trench 11,022 m (36,161 ft)
Highest continental mountain Mt. Everest 8850 m (29,935 ft)

8. Fig. 1.3cd

9. Exe. 01-01 Name principle oceans on the earth.
Do you think if “earth” is misnamed for
our planet? Why?

10. Scientific method Observations Hypotheses
Testing and modification of hypotheses
Theory
Probably true versus absolutely true
Science is continually developing because of new observations

11. Scientific method
Fig. 1.9

12. Density Density is defined as: Mass of unit divided by Volume of unit
 = m / V
Example:
A rock has a mass of 5000 Kg
Its volume is 2 m3
 = m / V
 = 5000 Kg / 2 m3
 = 2500 Kg/m3

13. Density stratification
Protoearth experiences density stratification
Density = how heavy something is for its size
Density stratification causes high density material to sink while low density material rises
High density material = rock material and metals
Low density material = gases

14. Origin of the Solar System and Earth
Cloud of gas and space dust (nebula) began to contract about 4.6 billion years ago
The Nebular Hypothesis

15. Origin of the Solar System and Earth
Protoplanets were created from the nebula
Protoearth was initially homogenous:
Larger in size than today’s Earth
Had lots of volcanic activity
No continents or oceans
No life

16. Origin of Earth’s atmosphere
Partial melting resulted in outgassing about 4 billion years ago
Similar to gases emitted from volcanoes
Mainly water vapor
Carbon dioxide, hydrogen
Other gases such as methane and ammonia

17. Origin of Earth’s oceans
Water vapor released by outgassing
Condensed as rain
Accumulated in ocean basins
About 4 billion years ago
Ice Comets were also important to adding water to the Earth system

18. Fig. 1.17

19. Ocean salinity Rain dissolves rocks
Dissolved compounds (ions) accumulate in ocean basins
Ocean salinity based on balance between input and output of ions
Ocean salinity nearly constant over past 4 billion years

20. Exe
Please describe how our solar system, the atmosphere and ocean were formed on the earth?
What is density stratification?
Why is sea water salty?

21. Earth’s internal structure
Highest density material at center (core)
Lowest density material at surface (crust)
Earth layered
Chemical composition
Physical properties

22. Chemical composition Crust Low-density, mainly silicate minerals
Mantle
Mainly Fe and Mg silicate minerals
Core
High-density, mainly Fe and Ni

23. Layered Earth
Fig. 1.14

24. Physical properties Lithosphere Asthenosphere Mesosphere Outer core
Inner core

25. Physical properties Lithosphere Asthenosphere Cool, rigid, brittle
Surface to about 100 km (62 miles)
Asthenosphere
Warm, plastic, able to flow
From 100 km to 700 km (430 miles)

26. Fig. 1.15

27. Lithosphere Oceanic crust Underlies ocean basins Igneous rock basalt
Average thickness 8 km (5 miles)
Relatively high density
3.0 g/cm3

28. Lithosphere- Crust and Uppermost mantle fused together.
Continental crust
Underlies continents
Igneous rock granite
Average thickness 35 km (22 miles)
Lower density
2.7 g/cm3

29. Asthenosphere Upper mantle Plastic—deforms by flowing
High viscosity—flows slowly

30. Exe
In terms of chemical property, how many layers does the earth have? List them.
In terms of physical property, how many layers does the earth have? List them.

31. Life in oceans
Earliest life forms fossilized bacteria in rocks about 3.5 billion years old
Marine rocks
Life originated in oceans?

32. Stanley Miller’s experiment
Organic molecules formed by ultraviolet light, electrical spark (lightning), and mixture of water, carbon dioxide, hydrogen, methane, and ammonia

33. Fig. 1.18a

34. Age of Earth Radiometric age dating
Spontaneous change/decay
Half-life
Earth is about 4.6 billion years old

35. Geologic time scale
Fig. 1.H

36. Exe
How old is the earth? When did life start on the earth? How do we know these?

37. Summary General Information: earth, oceans Scientific Methods
Origin of Earth, Ocean, Atmosphere
Internal Structure of Earth