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Ch 2 Earth’s Size & Shape. I. Model A representation of an object, a process, or a phenomenon. Ex. – Globe – best, most to scale model of the Earth –

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Presentation on theme: "Ch 2 Earth’s Size & Shape. I. Model A representation of an object, a process, or a phenomenon. Ex. – Globe – best, most to scale model of the Earth –"— Presentation transcript:

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 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. II. A System

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

5 Structure of the Earth Cont’ C.Mantle - largest Earth layer  composed of silicon, oxygen, magnesium, & iron D.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  1 0 C 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 A.Evidence that Earth is Spherical 1.The mast of a ship is the 1st part to appear over the horizon & the last to disappear.

10 Earth From Space 2.Photographs of Earth from space

11 Earth’s Shape Cont’ 3.An eclipse of the moon occurs when Earth's shadow falls on the moon  The shadow is always an arc of a circle http://www.rit.edu/~andpph/eclipse-01-20-00.htmhttp://www.rit.edu/~andpph/eclipse-01-20-00.htm l

12 4.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 Earth’s Shape Cont’

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 A. Density – The amount of matter (mass) in a given space (volume) Average density = 5.5 g/cm 3

16 VII. Measuring Earth's Circumference A. 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 1 st Scientific Measurement of Earth’s Circumference Went blind 195 BC Starved himself to death 194 BC

18 Facts Eratosthenes knew: At noon on June 21 st (Summer solstice): The sun casts a shadow of 7.2 o 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 1. Atmosphere 2. Geosphere 3. Hydrosphere 4. Biosphere

22 1. Atmosphere Atmos- Greek, Meaning vapor – Ozone- O 3, 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


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