ch 2 earth’s size & shape. i. model a representation of an object, a process, or a phenomenon....
TRANSCRIPT
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
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
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
Structure of the Earth Cont’
C. Mantle - largest Earth layer composed of silicon, oxygen,
magnesium, & ironD. Crust - outer most layer of Earth
the deepest mines & caves go no further than the crust
thicker under the continents than the ocean
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)
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.
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.htm l
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’
B. Oblate Spheroid
Sphere that is slightly flattened at the poles & bulged at the equator
Caused by Earth's rotation
VI. Earth’s Density
A. Density – The amount of matter (mass) in a given space (volume)
Average density = 5.5 g/cm3
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
Eratosthenes Cont’
Lived in Egypt1st Scientific Measurement of Earth’s
CircumferenceWent blind 195 BC Starved himself to death 194 BC
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)
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)
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
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
3. Hydrosphere
Hydro- Greek meaning water– All the water of the Earth’s System
OceansGlaciersGroundwaterRiversLakes