(7) Planet Blue

The Arctic Regions

BP7

Polar Regions

Earth is divided into two Polar Regions: North Polar Region and South Polar Region. These regions are very cold and remain covered with snow for most of the year. They include the Arctic Ocean, Greenland, and Siberia in the North Polar Region and the Antarctic in the South Polar Region.

• In the polar region, the sun never rises in winter.

• In the polar region, the sun never sets during the summer.

• The southern polar region is called Antarctica.

• The northern polar region is called the Arctic.

• Fram Basin at –14,070 feet below sea level is the lowest point in the Arctic.

• Bentley Sub glacial Trench at –8,200 feet below sea level is the lowest point in Antarctica.

• The Arctic poppy and reindeer moss are plants grown in Arctic regions.

• William Edward Parry, a British naval officer, undertook one of the earliest expeditions to the North Pole in 1827.

 Permafrost

The layer beneath the arctic lands is a frozen layer of soil, which is called permafrost.

 Muskeg

Low-lying bushes and grasses in the Arctic regions are known as muskeg.

 Time Zones

Time zones are imaginary divisions of the earth. Earth is divided into 24 time zones, which are separated by 15° in longitude. Each time zone has the same time everywhere within it. The zones start at 0° in Greenwich, England.

• Mean solar time is based on the earth’s rotation relative to the sun throughout the year.

• British Railways established the first time zone in the world on December 1, 1847.

• Greenwich mean time (GMT) was established in 1675.

• Most major countries had adopted hourly time zones by 1929.

• Sanford Fleming divided the world into 24 time zones, each spaced at 15 degrees in longitude.

• The International Date Line is an imaginary line opposite the Prime Meridian, which offsets the date as one travels east or west across it.

 Day of Two Noons

"The Day of Two Noons" is the time zone adopted by the United States and Canadian railroads on November 18, 1883.

Sanford Fleming

In 1878 Canadian Sir Sanford Fleming was the first to propose the system of time zones for the entire world.

 Soil is the surface layer of Earth.

It is a mixture of rock particles, organic matters, and water molecules. Physical and biological agents along with climatic conditions generally form soil. Soil is composed of different layers: organic matter, surface soil, subsoil, and substratum.

Types of Soil

There are 12 types of soil: Alfisols, Aridisols, Entisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, Gelisols, Andisols, and Vertisols.

• Pedology is the scientific study of soil.

• Humus is the top layer of soil, made up mostly of leaf litter and decomposed organic matter.

• Topsoil is the dark-colored layer below the humus, which grow seeds and plant roots.

• The eluviation layer is a light-colored layer beneath the topsoil, which is composed of sand and silt.

• The subsoil is the layer beneath the eluviation layer, made of clay and mineral like iron, aluminum oxides, and calcium carbonate.

• The regolith is the layer beneath the subsoil, which consists of slightly broken-up bedrock.

• Bedrock is the layer beneath all the other soil layers.

Composition of Soil Sample

An average soil sample consists of 45 percent minerals, 25 percent water, 25 percent air, and 5 percent organic matter.

 Pedology is the scientific study of soil.

• Humus is the top layer of soil, made up mostly of leaf litter and decomposed organic matter.

• Topsoil is the dark-colored layer below the humus, which grow seeds and plant roots.

• The eluviation layer is a light-colored layer beneath the topsoil, which is composed of sand and silt.

• The subsoil is the layer beneath the eluviation layer, made of clay and mineral like iron, aluminum oxides, and calcium carbonate.

• The regolith is the layer beneath the subsoil, which consists of slightly broken-up bedrock.

• Bedrock is the layer beneath all the other soil layers.

 Types of Soil

There are 12 types of soil: Alfisols, Aridisols, Entisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, Gelisols, Andisols, and Vertisols.

 Continents

 Earth is divided into large pieces of continuous land masses, known as continents.

Continents cover around 29 percent of Earth’s total area. Asia, Europe, North America, South America, Australia, Africa, and Antarctica are the seven continents. Asia is the largest and Australia is the smallest continent.

 Total Number of Continent Plates

The current continental and oceanic plates include: Eurasian plate, Australian-Indian plate, Philippine plate, Pacific plate, Juan de Fuca plate, Nazca plate, Cocos plate, North American plate, Caribbean plate, South American plate, African plate, Arabian plate, Antarctic plate, and Scotia plate.

 • Alfred Wegener, a German geologist and meteorologist, first proposed the theory of continental drift in 1912.

• The continental drift states that the seven continents were formed from a single land mass or super continent, Pangaea.

• During the Jurassic period, Pangaea started to break up into two smaller super continents, called Laurasia and Gondwanaland.

• Modern-day continents formed by the end of the Cretaceous period.

• Plate tectonics theory states that the earth’s plates are moving constantly at a rate of about 3.93 inches per year.

 SUN

 The sun is the source light, heat, and other forms of energy on Earth. All weather phenomena occur due to uneven heating of Earth by the sun. This causes temperature differences, which lead to global wind, cloud formation, rain, snow, and thunderstorms.

The sun also influences the magnetic properties of the upper atmosphere of Earth, which affects our communication and energy systems.

• Solar energy reaches Earth in less than 9 minutes.

• About 34% of the solar energy reaching the troposphere is reflected back into space by clouds, dust, and chemicals.

• Solar radiation reaches Earth's upper atmosphere at a rate of 1,366 watts per square meter.

• A Trombe wall is a solar heating and ventilation system.

• A solar box oven traps the sun's energy to cook food.

• In 1767 Horace de Saussure made the first known western solar oven.

• Solar cells generate electricity from sunlight.

 Use of Solar Energy

Solar energy can be used in a number of applications such as heating, electricity generation, and desalination of seawater.

 Natural Greenhouse Gases

Natural greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The sun is the source light, heat, and other forms of energy on Earth. All weather phenomena occur due to uneven heating of Earth by the sun. This causes temperature differences, which lead to global wind, cloud formation, rain, snow, and thunderstorms. The sun also influences the magnetic properties of the upper atmosphereof Earth, which affects our communication and energy systems

 

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