• DIURNAL AND ANNUAL MOTION OF THE EARTH
    PHYSICAL GEOGRAPHY

    DIURNAL AND ANNUAL MOTION OF THE EARTH

    Everyday the sun rises in the east and sets in the west. This process led many people in the past to think that the sun is moving and the earth is fixed. The sun moves around the earth. But with the advancement of science, this has been proved that the sun itself is moving and the earth has also motion. Later it has been revealed that the sun does not move around the earth, rather the earth moves around the sun. The earth not only moves around the sun, it also rotates on its own axis. The motion of the earth is of two types : (1) to rotate on…

  • THE ROCKS OF THE EARTH
    PHYSICAL GEOGRAPHY

    THE ROCKS OF THE EARTH

    The earth’s crust consists of rocks. A rock is any mineral material of the earth. It may be a combination of different mineral elements such as silica which contains silicon and oxygen. All the rocks differ from one another in texture, structure, colour, permeability, mode of occurrence and degree of resistance to denudation.   TYPES OF ROCK All rocks are classified into three major types: igneous rocks, sedimentary rocks, metamorphic rocks based on their origin (mode of formation) and appearance.   Igneous Rocks Characteristics Igneous rocks are crystalline in structure i.e. they contain crystals. They do not occur in layers i.e. they are non-stratified rocks. They do not contain fossils.…

  • THE EARTH’S ROTATION AND REVOLUTION
    PHYSICAL GEOGRAPHY

    THE EARTH’S ROTATION AND REVOLUTION

    The earth moves in space in two different ways. These are: Rotation Revolution   ROTATION OF THE EARTH Rotation of the earth is defined as the movement of the earth round the sun on its axis. The earth moves or rotates on its axis from west to east. The rotating earth is inclined at an angle of 23 1/2°along its axis. It takes the earth twenty-four hours (i.e. a day) to complete one rotation (i.e. the earth rotates through 360° in every 24 hours). The rotation of the earth causes day and night. This is why it is said that there are twenty-four hours in a day. That is, twelve…

  • MORE DETAILS ABOUT THE OUTER AND INTERNAL STRUCTURE OF THE EARTH
    PHYSICAL GEOGRAPHY

    MORE DETAILS ABOUT THE OUTER AND INTERNAL STRUCTURE OF THE EARTH

    The structure of the earth is grouped into two zones. These are the outer structure and the internal structure.   THE OUTER STRUCTURE OF THE EARTH The outer structure of the earth is made up of four zones or layers. These zones or layers are: Lithosphere. Hydrosphere. Atmosphere. Biosphere.   LITHOSPHERE (CHARACTERISTICS) The lithosphere is the solid portion of the earth. It is the outermost layer or zone of the earth crust. It is made up of rocks and mineral materials. It represents 30% of the earth surface. It forms the land mass which is about 10-50km thick. The outermost layer of the land mass is made up of loose…

  • LEARN ABOUT THE STRUCTURE AND COMPOSITION OF THE EARTH
    PHYSICAL GEOGRAPHY

    LEARN ABOUT THE STRUCTURE AND COMPOSITION OF THE EARTH

    Isaac Newton was one of the first scientists to theorize about the structure of Earth. Based on his studies of the force of gravity, Newton calculated the average density of Earth and found it to be more than twice the density of the rocks near the surface. From these results, Newton realized that the interior of Earth had to be much denser than the surface rocks. His findings excluded the possibility of a cavernous, fiery underworld inhabited by the dead, but still left many questions unanswered. Soon after the Earth formed, unique processes occurred – division into metallic core, silicate mantle and crust – which, along with surface water, made…

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