3. Earth Science
Geologic Time Scale
Two time scales
Radiometric
Based on natural
radioactivity of
chemicals in rocks
Relative
Based on sequence of
layering of rocks and
evolution of life.
5. Earth Science
Earth Structure
4.6billion years ago.
3 Sections
Biosphere – All forms of life
Hydrosphere – All forms of water
Internal Structure – Crust, mantle, core
7. Earth Science
Tectonic Plate Theory
Continental Drift
Continents were once Pangaea
Similar rock layers with similar fossils
Seafloor Spreading
Magnetic rock patterns found on either side
of ocean ridges
Explains
mountains, volcanoes,
earthquakes
11. Atmosphere
Zones
Troposphere
Closest to Earth
Convection Currents
Stratosphere
Less dense
Contains most Ozone
Mesophere
Thermosphere
Heated by solar and cosmic radiation
13. Atmosphere
Rain Shadow Effect
Clouds release moisture as they rise,
windward side of mountains receive
rainfall, leeward side does not and
becomes desert.
Places with high level of precipitation also
have high levels of atmospheric
circulation.
Includes regions with colliding air masses,
windward side mountains, around equator
14. Atmosphere
Kyoto Protocol
1997
160 countries agree to reduce
greenhouse gas levels by
2012 to below 1990 levels
Has been signed by all
industrialized countries except
Monaco, Liechtenstein,
Australia, and United States
Poor countries are exempt to
encourage development
17. Water
Distribution
97.6% of all water is oceanic saltwater
Freshwater is not easily found
87.2% of freshwater is in glaciers/ice caps
12% is groundwater
.8% is surface water
45.7% is in lakes/reservoirs
23.8% in soil moisture
23.8% in plants and animals
4.8% in atmosphere
1.3% in wetlands
.6% in rivers and streams
20. Water
Shortages
1 billion people lack access to safe
drinking water
2.6 billion people don’t adequate
sanitation
Future wars will be fought over water
rather than oil.
21. Water
Dams
Pros
Stores water
Generates renewable power
Cons
Structure failure is disastrous
Displaces people and wildlife
Kills fish
Sediment limits reservoir life
24. Soil
Soil Characteristics
Thintop layer of the Earth’s surface
Basic natural resource
Holds nutrients and water for plants and
animals
Water is filtered and cleansed as it flows
through soil
25. Soil
Soil Composition
Three main ingredients
Minerals of different sizes (sand, silt and
clay)
Organic materials from dead organisms
Open space
Good soil has 45% minerals, 5% organic
matter, 25% air, and 25% water.
28. Soil
Rock Cycle
Three main categories of rock include:
Metamorphic
Slate and marble
Igneous
Granite and basalt
Sedimentary
Sandstone, shale, and limestone
