The Water Cycle The total amount of the earth’s water doesn’t change nor does it stay on one place. It is constantly moving from the oceans, to the.

The Water Cycle

• The total amount of the earth’s water doesn’t change nor does it stay on one place. It is constantly moving from the oceans, to the air, to the ground, & back to the oceans.

• There are 3 main phases: 1. evaporation 2. condensation 3. precipitation

• Evap – this occurs when the sun’s heat turns liquid water into a water vapor (called humidity) & moves into the air

• The vapor changes back into a liquid, which is called condensation. Tiny droplets of water come together to form clouds.

• The water falls from the clouds as precipitation.

• The water soaks into the ground & collects into streams & rivers & move back to the oceans.

1. Freshwater – Only about 3% of the earth’s water is freshwater. Of that, almost 2% is frozen in ice & glaciers.

- Lakes, rivers, & groundwater make up the rest of the freshwater.

Types of Water

2. Salt Water – Ocean water makes up about 97% of the earth’s water.

- There are 5 major oceans.

1.Pacific – the largest. It covers about 63 million sq. miles, making it larger than all the land mass combined. It’s name comes from a Latin word, which means “peaceful sea” & was named by Magellan.

2. Atlantic – 2nd largest;

- is about 31 million sq. miles & is the most traveled ocean. Its name comes from Atlas of Greek mythology.

3. Indian – 3rd largest; Asia is to the north & Africa to the west.

4. Arctic – smallest ocean; lies almost entirely around the Arctic Circle.

5. Southern – named in 2000, it completely surrounds Antarctica.

• Weather – the constant change in the air during a short period of time. It changes from day to day.

• Climate – the usual pattern of weather events in an area over a long period of time.

Types of Climates1. Tropical – This climate

gets its name from the tropics, which are located b/w the Tropic of Cancer & the Tropic of Capricorn.

These are almost always warm & moist.

- There are 2 types of Tropical Climates

1. The tropical rain forest – wet most of the year.

2. The tropical savanna climate – has 2 seasons, one wet, one dry.

2. Mid-Latitude Climate – Most of the world’s people live in this region. There is a good bit of variety.

Warm air comes from the Tropics, & cool air comes from the polar regions. Temps. change from season to season.

- There are 4 types of MLCs:1. Marine West Coast Climate2. Mediterranean Climate3. Humid Continental Climate4. Humid Subtropical Climate

3. High-Latitude Climates – are cold everywhere- 3 Types:1. Subarctic Climate – very few people live here. Huge evergreen forests called taiga are here.2. Tundra Climate – tundra, vast treeless plains, are here. This area is harsh & dry, & the lower layers stay frozen all the time.

3. Ice Cap Climate – huge sheets of polar ice ; no vegetation here, except funguslike plants & moss that grows on rocks

4. Dry Climates – These receive little or no rainfall. Temps are extremely hot during the day & cold at night.

- 2 Types of Dry:

1. Desert Climate- receive less than 10” of rain per year.

2. Steppe Climate- Many deserts are surrounded by partly dry grasslands & prairies known as steepes.

The Wind & Ocean Currents Effects on Climate

• Winds follow patterns, & they move north, south, east, & west.

• El Nino – forms when cold winds from the east are weak. W/o these winds, the Pacific grows warmer than usual. More water evaporates & more clouds form. Some areas get lots of rain, while others get very little.

- are believed to occur about every 3 years.

• La Nina – the exact opposite of El Nino. - Winds from the east become very

strong, cooling the Pacific. Heavy clouds form in the Pacific.

• Ocean Currents – Moving streams of water, called currents, carry warm & cold water through the world’s oceans.

- These currents effect the climate of land areas.

The Impact of People on Climate

• The burning of coal, oil & natural gas as energy sources releases certain gases into the air.

• The buildup of these gases can be dangerous.

• It causes the greenhouse effect.

•The gases prevent the warm air from rising & escaping into the atmosphere.

• As a result, the overall temp. of the earth will increase.

• Some scientists predict terrible results from this global warming, but others argue that the world isn’t warming.

• The atmosphere, a thin layer of gases, is made up mostly of nitrogen & oxygen.

• The condition of the atmosphere varies from day to day, season to season.

• Once the sunlight is absorbed, it is changed into heat energy.

• When the sunlight is changed into heat, the Earth’s surface & atmosphere warm up. The measurement of heat is called temperature.

The Earth’s Atmosphere

• Human actions have environmental effects on the atmosphere.

• The ozone layer is a region in the atmosphere that blocks ultraviolet radiation from the Sun.

• UV rays can cause many problems (EX: Skin cancer)

• B/C of pollution, there is now a hole in the ozone.

• The hole is located over Antarctica & was 1st noticed in the 1970’s.

• Many types of pollution have been the cause of the ozone hole.

• ChloroFluroCarbons (CFCs) are a major contributor to the ozone depletion.

• CFCs are found in refrigeration systems, air conditioners, and aerosols.

• Another problem is nitrogen oxides, which are found in aircraft & automobiles.

The Biosphere is the part of the Earth where all

the living organisms live.

Rainforests are being destroyed

every day.

A large reason is b/c of the logging companies that

deforest, or clear the land to

harvest trees.

The worst destruction is in Brazil, Indonesia, SE Asia, South America & Mexico

50% of all plants & animals on Earth live in rainforests.

• Desertification is the process which turns productive land into desert land b/c of poor land management.

• This occurs on land that borders deserts.

• The deserts are growing.

Examples: Desertification in China

Causes of desertification:

1. Overgrazing of animals

2. Destruction of vegetation

3. Accidental burning of vegetation

4. Incorrect irrigation practices

Water is lost off the land instead of soaking into the soil to provide

moisture for the plant.

The Lithosphere

is the solid part of the Earth

consisting of the crust &

outer mantle

• One problem is land degradation, the natural reduction of the Earth surface caused by erosion of wind or water & loss of elements from soil, pollution & another is salinization, when large amounts of salt get into the soil due to improper irrigation.

The Lithosphere

Causes of Land Degradation:

1. Hurricanes

2. Earthquakes

3. Areas subject to insect invasion

4. Drylands

5. Intensive grazing

6. The removing of vegetation & flooding

The Hydrosphere

is the watery layer of the Earth’s surface

Pesticides are chemicals used

to kill pests, esp. insects

• Sometimes they make their way into river systems & groundwater.

• They also affect our drinking water.

Positive Things We’re Doing for the Environment:

1. The Clean Air Act:

• Federal law passed in 1970

• Designed to make sure all Americans have air that is safe to breathe

• Requires the US EPA (Environmental Protection Agency) to set up nat’l standards to protect against pollutants

• State gov’ts must create clean-up plans to meet the health standards of the EPA (EX: clean-up of smog)

Positive Things We’re Doing for the Environment (con’t):

2. Prevent forest fires – the burning of fires causes pollution and reduces forest land

• Restocking fish –

replenishes loss of fish

3. Water purification

4. Awareness