Resumen Unidad 1english

Unit 1. The Earth. 1. How is the Earth? 1.1.- Shape (forma) The Earth is spherical, but not perfect, as it is flattened at the poles. It has got a minor vertical axis from the North Pole to the South Pole and a major horizontal axis at the level of the Equator. The shape of the Earth is known as a geoid. The equator is the parallel that divides the Earth into two equal hemispheres: North and South. 1.2.- Parts of the Earth. Geosphere: The geosphere is considered that portion of the Earth system that includes the Earth's interior, rocks and minerals, landforms and the processes that shape the Earth's surface. It is divided into three concentric layers: crust (oceanic crust and continental crust), mantle (upper mantle and lower mantle) and core (outer core and inner core). The crust and the most external part of the upper mantle form the Lithosphere, which is formed by solid materials that float over a layer of magma. Hydrosphere: it consists of all the water on Earth and includes all liquid and frozen surface waters, groundwater held in soil and rock, and atmospheric water vapour. Atmosphere: it is a layer of gases surrounding the Earth. According to their composition, temperature and density, it i s divided into five main layers (which we will study in unit 4). 1.3.- The Earth, a living planet. The Earth is the third planet of the solar system. The Solar System is within the Milky Way Galaxy. The Earth is the only planet in the Solar System where life exists. This is possible because of the presence of water, the existence of the atmosphere and the moderate temperature that our planet has got. 2.- The movements of the Earth. The Earth has got two main movements: rotation and orbit (also called translation). Rotation. It is the movement that the Earth describes spinning around its imaginary axis. The Earth completes one rotation in approximately every 24 hours. The rotation movement produces the succession of days and nights, as well as the time difference between the time zones. The earth is divided into 24 time zones. Orbit. The movement of the Earth around the Sun is called a revolution or orbit. The Earth takes 365 days and 6 hours approximately to complete a revolution. The revolution movement and the inclination of the Earth’s axis cause the seasons of the year. When it is summer in the northern hemisphere, it is winter in the southern hemisphere and vice versa because the sun rays are more perpendicular to one of them every time. 3.- Geographic network. Parallels and meridians form an imaginary grid over the Earth’s surface. Parallels are imaginary circumferences parallel to the Equator. The Equator divides the Earth into two hemispheres: northern hemisphere and southern hemisphere. The Equator is unique, but every parallel in the northern hemisphere has another equal one in the southern hemisphere. We have infinite parallels, but we use the main ones to divide the Earth into the main climate zones. Meridians are imaginary semicircles that go from the North Pole to the South Pole. The most important one is the Greenwich Meridian. Although we can draw infinite meridians, we have a main meridian every 15º which corresponds to each time zone. The Geographical Coordinates. Latitude is the distance between a point and the Equator from 0 degrees to 90 degrees. It can be North Latitude (positive latitude) or South L atitude (negative latitude). Longitude is the distance from a point to the Greenwich Meridian (also called Prime Meridian). It is measured from 0º to 180º. It can be East (positive) or West (negative) . Questions. 1.- How is the shape of the Earth? 2.- What is the Equator? 3.- Why is it possible life in our planet? 4.- What are the movements of the Earth? Explain something about each one. 5.- What are the latitude and longitude? How can we place a point in our planet using them? 6.- Can you make a brief written description of the picture in point 1.2 of this unit? Material de elaboración propia. Rafael Díaz. Dpto. CC.SS. Colegio Presentación. Baza (Gr)

Resumen Unidad 1english

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