Monday, 28 November 2011

The Gulf Stream

The world's oceans move constantly. Ocean currents flow in complex patterns and are affected by the wind, the water's salinity and temperature, the shape of the ocean floor, and the earth's rotation.
The Gulf Stream is one of the strongest ocean currents in the world. The Gulf Stream is a warm, Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean. At about 40°N 30°W, it splits in two, with the northern stream crossing to northern Europe (the North Atlantic Drift) and the southern stream recirculating off West Africa. The Gulf Stream influences the climate of the east coast of North America and the west coast of Europe.
The Gulf Stream brings warmth to the west coast of Europe and is the reason we have mild winters. Without this steady stream of warmth the British Isles winters are estimated to be more than 5°C  cooler, bringing the average December temperature in London to about 2°C.

Thursday, 24 November 2011

Köppen - climate classification system

Wladimir Köppen (1846-1940), was a Russian-born German climatologist who developed a systematic method of classifying the climates of the world based on long-term patterns of the distribution of temperature and precipitation around 1900. His classification remains the most used climate classification system up to the present day.

Köppen – climate classification system
Tropical climates

Tropical rainforest climate

Belém, Brazil
Tropical wet and dry / savanna climate
Lagos, Nigeria
Dry (arid and semi-arid) climates
Steppe climate
Denver, Colorado, United States
Desert climate
Dubai, United Arab Emirates
Temperate climates
Mediterranean climate, dry season in the summer
Barcelona, Spain
Temperate maritime climate, dry season in the winter
Zhengzhou, China
Temperate maritime climate, no dry season
Roermond, The Netherlands
Continental climates
Continental climate, no dry season
Chicago, Illinois, United States
Continental climate, dry in the winter
Vladivostok, Russia
Polar climates

Tundra climate
Vardø, Norway

Ice Cap climate

Highland climate
The Himalayas

Köppen – climate classification system - world map

Irrigation for agriculture

The next maps shows the world's most populated areas depend on irrigation for agriculture.

VIDEO - Irrigation for agriculture

Agriculture and irrigation have affected the rise and fall of many great civilizations. Without agriculture, our way of living would cease to exist as it does today. Without irrigation, we would not have agriculture.

Agriculture is the farming of crops. It provides most of the world's food supply and helps support the economy.

Irrigation is the act of moving water from one place to another and is used in farming to water crops.

Wednesday, 23 November 2011

The Water cycle

VIDEO - The Water cycle

VIDEO - The Water cycle 2

The water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapour, and solid at several places in the water cycle.

The sun, which drives the water cycle, heats water in oceans and seas. Water evaporates as water vapour into the air. Rising air currents take the vapour up into the atmosphere where cooler temperatures cause it to condense into clouds. Air currents move water vapour around the globe, cloud particles fall out of the sky as precipitation. Some precipitation falls as snow or hail.

Most water falls back into the oceans or onto land as rain, where the water flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, moving water towards the oceans. Not all runoff flows into rivers, much of it soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes aquifers, which store freshwater for long periods of time.

Over time, the water returns to the ocean, where the water cycle started.

Wednesday, 16 November 2011

Original vegetation of the world

Deserts of the world

Deserts cover about one-seventh of the earth's land surface. Desert regions cover 35% of the earth's surface.
Deserts are landscape forms or regions that receive little precipitation. They are cold at night and since the desert air is dry it holds little moisture. Desert regions receive an average annual precipitation of less than 250 mm.

European peninsulas



Colonization is when a group or groups or countries take over an area. Once in the area, the groups will set up settlements. These overseas settlements were called colonies. An example would be the early Dutch settlers in South Africa.

Tuesday, 15 November 2011

Friday, 11 November 2011

Five major circles of latitude

There are five major circles of latitude, listed below from north to south.

·         Arctic Circle (66.5° N)
·         Tropic of Cancer (23.5° N)
·         Equator (0° latitude)
·         Tropic of Capricorn (23.5° S)
·         Antarctic Circle (66.5° S)

Picture 1 of Tropic of Cancer

These circles of latitude, excluding the Equator, mark the divisions between the five principal geographical zones.


Also referred to as the torrid zone or tropical zone, all the water and land of the earth between the Tropic of Cancer and the Tropic of Capricorn. The tropics experience at least one day per year in which the sun passes directly overhead.

Tropic of Cancer

A line of latitude located at 23.5° north of the equator. The Sun is directly overhead the Tropic of Cancer on the summer solstice in the Northern Hemisphere (June 20 or 21). It marks the northernmost point of the tropics, which falls between the Tropic of Cancer and the Tropic of Capricorn.

Tropic of Capricorn

A line of latitude located at 23.5° south. The Sun is directly overhead the Tropic of Capricorn on the summer solstice in the Southern Hemisphere (Dec. 20 or 21). It marks the southernmost point of the tropics.

Arctic Circle

A line of latitude located at 66.5° north, delineating the Northern Frigid Zone of the Earth.

Antarctic Circle

A line of latitude located at 66.5° south, delineating the Southern Frigid Zone of the Earth.

File:Earth-lighting-summer-solstice EN.png

The creation of a rain shadow

Mountain ranges force air to rise along the windward side of the range; clouds form and precipitation falls. On the leeward side, dry air descends and warms. Little precipitation falls on this side, creating a rain shadow.

Creation of a rain shadow

Leeward: The side of a land mass sheltered from the wind—the opposite of windward.

Windward: The side of a land mass facing the direction from which the wind is blowing—the opposite of leeward.

Rain Shadow:The dry region on the leeward side of a mountain (the side sheltered from the wind). A place deprived of heavy rains because of a range of mountain sheltering it.

Evaporation, condensation, and precipitation cycles

Solar energy drives a cycle of evaporation, condensation, and precipitation.

Evaporation, condensation, and precipitation cycles

Variation in sunlight

Areas in the tropical regions receive sunlight directly. Regions further north and south receive incoming solar radiation at an angle, which reduces the heat and energy that reaches these areas.

Variation in incident sunlight

The sunlight intensity on some parts of the earth significantly varies over the course of the year as the earth changes its orientation in space. Seasonal variation in solar input occurs because the Earth is tilted on its axis by 23.5˚. As Earth orbits the sun, its orientation to the sun changes.
Winter in the northern hemisphere occurs as the northern tip of the planet tilts away from the sun. During this time, the southern hemisphere receives greater solar input and experiences summer. As Earth reaches the opposing point of its orbit and the northern hemisphere becomes angled toward the sun, the seasons reverse. Tropical regions experience relatively minor changes in temperature, and their seasons are characterized by the presence or absence of rain.


One of the most important climatic factors is temperature and it generally decreases with increasing latitude (as you go north) and altitude (as you go up).
In fact, scientists have determined that for every 1000 meters that we go up in altitude, there is a decrease in temperature of about 6 ° C.

That is equivalent to increase our latitude a linear distance of 500 to 750 km at the same elevation.

This rule, often called Humboldt's Rule, predicts that the plant communities will transform similarly with changes in temperature and altitude.

Relationship between latitude and altitude, copyright 1990 Wadsworth, Inc.

Languages in Europe

Tuesday, 8 November 2011


Tariffs are custom taxes that are imposed on imported goods. This raises the price of the import and gives an advantage to domestic products within that market. Tariffs are a barrier to trade and are used to protect a domestic industry.

VIDEO - Will tire tariffs cost consumers?

The American President is placing a 35 percent tax on tires made in China after labor unions complained that Chinese imports were forcing U.S. workers out of their jobs. What is the reaction to this news? Will these tariffs help decrease unemployment rates, or will they merely hurt consumers?

Wednesday, 2 November 2011

Five factors that affect climate

VIDEO - Five Factors that Affect Climate

The five factors that affect climate:

- altitude
- latitude
- near mountain range / topography
- distance to the sea
- prevailing winds / ocean currents