1. Ch 2 Earth’s Size & Shape

2. I. Model
A representation of an object, a process, or a phenomenon. Ex.
Globe – best, most to scale model of the Earth
Computer Climate models/Simulations

3. II. A System Part of the Universe that can be studied separately
Closed System- a system in which energy can enter or leave, but matter cannot
Open System- a system in which there is a free exchange of both energy & matter between the system & its surroundings.

4. III. Structure of the Earth
Inner Core - layer of the Earth composed of solid iron & nickel
Outer Core - layer of the Earth composed of liquid iron & nickel

5. Structure of the Earth Cont’
Mantle - largest Earth layer
composed of silicon, oxygen, magnesium, & iron
Crust - outer most layer of Earth
the deepest mines & caves go no further than the crust
thicker under the continents than the ocean

6. Layers of the Earth

7. IV.Temperatures Below the Surface
Deep caves stay about the same temperature all year
From 0 m to 20 m below, a cave usually remains equal to the avg. yearly temperature
Every 40 m below the 1st 20 m, the temperature in a cave 10C for each 40 m (120ft)

8. Heat is from:
Radioactive Minerals
Ex Uranium & Thorium
Compression of the crust by gravity

9. V. Earth’s Shape Evidence that Earth is Spherical
The mast of a ship is the 1st part to appear over the horizon & the last to disappear.

10. Earth From Space
Photographs of Earth from space

11. An eclipse of the moon occurs when Earth's shadow falls on the moon
Earth’s Shape Cont’
An eclipse of the moon occurs when Earth's shadow falls on the moon
The shadow is always an arc of a circle l

12. Earth’s Shape Cont’
Ships sailing north or south observed changes in the nighttime sky.
North Star appears higher in the sky as a ship travels north
Ships sailing south lose sight of the Big Dipper & begin to see the Southern Cross

13. B. Oblate Spheroid
Sphere that is slightly flattened at the poles & bulged at the equator
Caused by Earth's rotation

14. C. Weight on Earth

15. VI. Earth’s Density
Density – The amount of matter (mass) in a given space (volume)
Average density = 5.5 g/cm3

16. VII. Measuring Earth's Circumference
Eratosthenes (er uh Tos thuh neez)
Of Greek heritage, born in Cyrene, now Shah hat, (Libya)
Studied at Alexandria & Athens
Appointed Director of the Alexandrian Library, 236 BC

17. Eratosthenes Cont’ Lived in Egypt
1st Scientific Measurement of Earth’s Circumference
Went blind 195 BC
Starved himself to death 194 BC

18. Facts Eratosthenes knew:
At noon on June 21st (Summer solstice):
The sun casts a shadow of 7.2o from an obelisk in Alexandria
The sun cast no shadow in a well in Syene (called Aswan today)

19. Facts Eratosthenes knew:
Believed the suns rays hit the Earth as parallel lines
Eratosthenes figured Syene was due south of Alexandria (He was slightly off on this one)
Distance between Syene & Alexandria (925km) slightly off
Thought both cities were on the same line of longitude (off on this by 30)

20. VIII. Types of Data
Qualitative – data that is relative but not numeric.
Ex. The color of an object or stating someone is tall or taller than another person
Quantitative – data where a numeric measurement or a count of objects has been made

21. IX. 4 Spheres/Subdivisions of Earth
Atmosphere
Geosphere
Hydrosphere
Biosphere

22. 1. Atmosphere Atmos- Greek, Meaning vapor
Ozone- O3, protects Earth from Sun’s harmful UV rays
Oxygen & Carbon Dioxide provided for living things
Water vapor forms clouds

23. 2. Geosphere
Geo –Greek, meaning Earth
Rocks, Mountains, Beaches

24. 3. Hydrosphere Hydro- Greek meaning water
All the water of the Earth’s System
Oceans
Glaciers
Groundwater
Rivers
Lakes

25. 4. Biosphere Bio- Greek meaning Life
All forms of life on Earth from microscopic to Human