1. Chapter 2-1
Earth

2. Age of Earth 4.6 billion years old
Oldest rock: billion yrs old

3. The “watery planet” 70 % surface covered with water 97 % salt water
3 % fresh water

4. Earth’s Shape:

5. Oblate Spheroid: What causes this shape? Bigger at the equator
Polar circumference: 40,007 km
Equatorial circumference: 40,072 km
What causes this shape?

6. Atmospheric Composition
Nitrogen (N2) = %
Oxygen (O2) = %
Water (H2O) = 0 to 4% (variable)
Argon (Ar) = 0.93 %
Other gases

7. Role in space 3rd planet from the sun One satellite = moon
How does everything stay in orbit?

8. Gravity
the attraction between objects
Newton’s Law of Gravity

9. Newton’s Law of Gravity
Any two objects attract each other
More massive object, stronger the attraction
Closer two objects are, stronger attraction
End day 1

10. Earth’s Interior continued…
How do scientist know so much about the composition and location of each layer found in Earth?

11. Seismology
Study waves that are given off when an earthquake occurs.

12. Primary (P) and Secondary (S) Waves
P waves:
Move twice as fast as S waves
Move through rock or liquid
S waves:
Move only through rock
Change behavior according to material they pass through

14. Crust:
Accessible – top layer
Thinner under oceans than continents

15. Boundary between crust and mantle
Moho (Mohorovicic)
Detected by sharp increase speed of earthquake waves
Increase because of change in rock type

16. Mantle: Divided into three parts
Lithosphere: solid part of Earth,
crust and upper mantle
Asthenosphere: temp. of rock near melting pt.
Mesosphere: solid, molten rock

17. Asthenosphere 200-250 km below Earth’s surface
Temperature of rock near melting point
Molten rock from volcanoes
“Plastic” layer - rock flows very slowly

18. Core Outer core: Liquid because S waves don’t pass through iron
Creates Earth’s magnetic field

19. Earth’s Magnet Causes: Magnetosphere 1. Liquid Iron Core.
2. sun’s magnetic field
3. moon’s magnetic field
Magnetosphere

20. Inner Core Inner Core: End day 2 Mostly iron 9032-10832 degrees F
High pressure = solid
Doesn’t spin because solid
End day 2

21. Earth’s Gravity (day 3)
Newton’s Law of Gravity: force of attraction depends on what two things?

22. Weight Depends on: measure of the pull of gravity on an object
1. Mass
2. distance from Earth’s center
measure of the pull of gravity on an object
Unit = Newton (N)
1 kg of mass (on Earth)= 10 N

23. Weight changes with location
100 pounds on Earth =
Moon – 17 pounds
Jupiter – 254 pounds
Sun – 2790 pounds

24. Mass
Amount of matter something contains
Grams
Stays constant
end