Our Planet…

Onion Earth

• Earth has many layers• Lithosphere

– Solid surface of the planet

• Atmosphere– Gases surrounding the planet

• Hydrophere and Cryosphere– All water found on our planet

• Biosphere– All life on Earth

Layer 1: The Lithosphere

• Mineral vs. Rocks

– Minerals are:• Inorganic substances (don’t come from plants or animals)• Naturally occurring• Have a distinct mineral composition• Have well defined properties (due to composition and shape)

– Rocks are:• Heterogeneous solids composed of many minerals

Interesting facts on minerals:

– Characteristics to identify mineralsa) Colors

– A mineral that will always have the same color : idiochromatic

– A mineral that may vary in color: allochromatic

b) Hardness– Depends on atoms in the mineral– Mohs scale indicated the resistance to scratching

c) Transparency– Transparent/translucent/opaque

d) Streak

• Rocks:– Types of rocks

1. Igneous- Rocks formed when magma cools and solidifies

2. Sedimentary- Rocks formed by the accumulation and compaction of

debris

3. Metamorphic- Rocks that have been transformed by heat or pressure

Rocks to soil…

• Through the wind and water erosion as well as freeze and thaw, erodes the rocks.

• Soil is produced– As soil develops it thickens and forms distinct

layers (a.k.a. horizons)

Soil horizons• Horizon O: Organic Matter

– Mostly made up of organic matter• Horizon A: Topsoil

– Supports plant life– Mixture of minerals and organic matter

• Horizon B: Subsoil– Made of small mineral particles– Tree with deep roots, take in nutrients

• Horizon C: Fragmented Parent Rock– Also called substratum– Formed by the disintegration of the underlying

parent rock• Horizon R: Unaltered parent rock

– Starting point of soil formation

Issues with soil…

• What makes soil fertile?– Sufficient amount of minerals– Sufficient amount of moisture– Appropriate pH

• pH that is not optimal will limit the absorption of nutrients

• A soil’s buffering capacity is its ability to resist pH changes. The finer the texture of the soil the better it will resist pH change.

Energy Resources

• Fossil Fuels– Includes oil, coal and natural gas

• Oil and natural gas result from the decomposition of marine animals and algae

• Coal results from the decomposition of organic plant matter

– Advantages– Disadvantages

• Nuclear• Geothermal

Isotopes

• Isotopes: Element with the same number of protons, but different number of neutrons.

MassAtomic number

The Atmosphere

The atmosphere

• The atmosphere– Acts as a screen against harmful radiation– Retains heat allowing for life on Earth– Includes O2 necessary for cellular respiration

and CO2 necessary for photosynthesis

– Our atmosphere covers our planet because of the gravitational field of our planet

Composition of the air• Atmosphere: layer of gas (especially nitrogen

and oxygen) that surrounds our planet

• Air is made up of:– 78% Nitrogen (N)– 21% Oxygen (O2)– 1% of other gases

• Water Vapor• CO2• Argon• …

Atmospheric layers• Troposphere: (0-15km)

– Where meteorological phenomenon occur

• Stratosphere: (15-50 km)– Ozone layer– Temperature increases due to ozone layer

• Mesosphere: (50-80 km)– Coldest layer of the atmosphere (-80C)

• Thermosphere: (80-500 km)– Hottest layer of the atmosphere (1800C)

• Exosphere: (500 km and up)– Where satellites are placed

Atmospheric pressure

• Air is a fluid• Atmospheric pressure

– Is the weight per unit area (pressure) of the column of air above that location.

• the pressure of the air in the atmosphere• Varies with time and place

• To measure pressure we use a barometer• Units of measurement = Pascals• Average air pressure at sea level = 102.325 Pa

Factors affecting atmospheric pressure

• If the number of air particles – Increase : then pressure increases– Decrease: then pressure decreases

• There is a natural thinning of our atmosphere with altitude and therefore a natural decrease in pressure

• If temperature of the air– Increase: (the molecules are flying every which way)

the pressure will decrease– Decreases: the pressure will increase– **Warm air is therefore less dense than cold air

Another interesting factor

• Water vapor– If the amount of water vapor increases: the air

pressure will actually decrease, because humid air is actually less heavy than dry air.

What does all this mean?

• Because density changes with the temperature, the atmosphere will undergo “atmospheric circulation”

– Atmospheric circulation is the global-scale movement of the layer of air surrounding the Earth

• Which really comes down to… atmospheric circulation is the global-scale movement of the atmosphere

Atmospheric Circulation

Coriolis Effect

• Definition:

• Winds deviate to the right in the Northern Hemisphere

• Winds deviate to the left in the Southern Hemisphere

Circulation cells1. Hadley Cells

• Between the equator and 30th latitude• Warm air rise at equator• Creates the trade wind

2. Ferrel cells– Between the 30th latitude and 60th latitude– Creates the westerlies (from west to east)

3. Polar Cells– Between the 60th latitude and the poles– Creates the polar easterlies (from east to west)

Prevailing winds• Definition:

– Major atmospheric current that blow in a given direction according to global patterns of movement near the surface.

• Between– Equator and 30th parallel

• Tropical easterlies or trade winds– 30th parallel and 60th parallel

• Westerlies– 60th parallel and pole

• Polar easterlies

Other winds• Regionally,

– winds do not always blow in the same direction as the prevailing winds. They are affected by local high pressure and low pressure system

• Jet streams– Subtropical Jet stream

• Around the 30th parallel• Travels at 400 km/h 11 km above the surface

– Polar jet stream• Around the 60th parallel• Travels at 300 km/h

Weather Makers

Air Masses, anticyclones and cyclones

1. Air masses

• Definition:– Large expanse of the atmosphere with

relatively uniform temperature and humidity.

– Air mass characteristics:• Humidity (humid or dry)• Temperature (cold or warm)

1. Air masses

• When air masses collide they create fronts. They do not mix.

a) Cold Frontb) Warm Frontc) Stationaryd) Occluded

a) Cold front• Occurs when…

– A cold air mass overides a warm air mass

• Symbol

• Weather– The warm air rises abruptly, causing the water vapor

to rise and condense and produces storm clouds

a) Cold Front

b) Warm front• Occurs when…

– A warm air mass overides a cold air mass

• Symbol

• Weather– The warm air rises slowly, causing the water vapor to

rise and condense and produces clouds

b) Warm Front

c) Stationary Front• Occurs when…

– A warm air mass meets head on a cold air mass

• Symbol

• Weather– The masses collide, the warm air rises over the cold

denser air, causing the water vapor to rise and condense and produces clouds and rain on the cold front

d) Occluded Fronts

• Occurs when…– A cold front catches up with a warm front

• Symbol

• Weather– The cold front catches up with the warm front

and forces it from the ground

d) Occluded Front

2. Cyclones and anticyclones

• A cyclone:– Area of low atmospheric pressure. The air turns

counterclockwise in the Northern hemisphere and clockwise in the Southern Hemispheres.

• An anticyclone:– Area of high atmospheric pressure. The air turns

clockwise in the Northern hemisphere and counterclockwise in the Southern Hemispheres.

• Hurricanes:– A large cyclone characterized by violent winds

Atmospheric issues

• Smog– Thick layer of fog and smoke and atmospheric

pollutants• Ozone layer thinning• Contaminants

– Acid Rain, smog, toxic chemicals, dust and ozone destruction

• Greenhouse gases– Climate change: abnormal modification of climatic

conditions on Earth, caused by human activity

Energy resources

• Solar energy• Wind energy

The Hydrosphere

Water, water everywhere?

The Hydrosphere

• Definition:– Earth’s outer layer of water, uniting water in all

its state: liquid, gas, solid.

– Of this, 2.5% is freshwater• Of this, 79% is frozen

Redividing the Hydrosphere

• We can “separate” the hydrosphere into 3 general categories:– Inland water– Ocean water– The Cryosphere

Inland water

• Definition– Fresh water bodies found on continents. This unites

rivers, lakes and groundwater

• How do we manage and study inland water?– We divide the continent up into watersheds

• A watershed is an area of land in which all the water in it drains to the same point/larger body of water)

Watersheds

• Definition:– A watershed is an area of land in which all the water

in it drains to the same point/larger body of water)

• Criteria to consider while deciding a watershed:• Topography• Geology• Climate• Vegetation• Agriculture

The cryosphere

• Definition:– Consists of all frozen water on the Earth’s surface

– The cryosphere encompasses:• Pack ice• Glaciers• Permafrost• Frozen lakes and rivers• Snow (etc.)