The Four Realms of the Earth

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1. THE FOUR REALMS OF THE EARTH

2. A  lithosphere   is the rigid , outermost shell of a rocky  planet , and can be identified on the basis of its mechanical properties. On  Earth , it comprises the  crust  and the portion of the upper  mantle  that behaves elastically on time scales of thousands of years or greater. The outermost shell of a rocky planet, the crust, is defined on the basis of its chemistry and mineralogy 2 LITHOSPHERE

3. CONTINENTS 3 There are seven continents. There are: Asia Africa North America South America Antarctica Europe Australia

4. Structure of the Earth 4 Earth's lithosphere includes the crust and the uppermost mantle, which constitute the hard and rigid outer layer of the Earth. Earth's  inner core  is Earth's innermost part and is a primarily  solid   ball  with a  radius  of about 1,220  km. Earth's  outer core  is a liquid layer about 2,266 km thick composed of  iron  and  nickel  that lies above Earth's solid  inner core  and below its  mantle . Its outer boundary lies 2,890 km beneath Earth's surface. 

5. CRUST 5  the  crust  is the outermost solid shell of a rocky  planet  or  natural satellite , which is chemically distinct from the underlying  mantle . The crust of the  Earth  is composed of a great variety of  igneous ,  metamorphic , and  sedimentary rocks .

6. MANTLE 6 Earth's mantle is a silicate rocky shell about 2,900 kilometres (1,800 mi) thick [1]  that constitutes about 84% of Earth's volume. [2]  It is predominantly solid but in geological time it behaves like very viscous liquid. The mantle encloses the hot core rich in iron and nickel, which occupies about 15% of Earth's volume.

7. CORE 7 Earth's  inner core  is Earth's innermost part and is a primarily  solid   ball  with a  radius  of about 1,220  km. It is believed to consist primarily of an  iron – nickel   alloy  and to be approximately the same temperature as the surface of the  Sun : approximately 5430  ° C.

8. ROCKS:IGNEOUS 8 There are three types of rocks. They are: Igneous rocks: Igneous rock   derived from the  Latin   word ignis meaning fire. Igneous rock is formed through the cooling and solidification of magma  or  lava . Igneous rock may form with or without  crystallization , either below the surface as  intrusive  ( plutonic ) rocks or on the surface as  extrusive  ( volcanic ) rocks. This magma can be derived from partial melts of pre-existing rocks in either a planet's  mantle  or  crust .

9. ROCKS:SEDIMENTARY 9 Sedimentary rocks  are types of  rock  that are formed by the  deposition  of material at the  Earth 's surface and within bodies of water.  Particles that form a sedimentary rock by accumulating are called  sediment . Before being deposited, sediment was formed by  weathering   and erosion  in a source area, and then transported to the place of deposition by  water ,  wind ,  ice ,  mass movement  or  glaciers  which are called agents of denudation .

10. ROCKS:METAMORPHIC 10 Metamorphic rocks make up a large part of the  Earth 's  crust  and are classified by texture and by  chemical  and  mineral  assemblage ( metamorphic facies ). They may be formed simply by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from  tectonic  processes such as continental collisions, which cause horizontal pressure, friction and distortion. They are also formed when rock is heated up by the  intrusion  of hot molten rock called  magma  from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are  gneiss ,  slate ,  marble ,  schist , and  quartzite .

11. ROCK CYCLE 11 The  rock cycle  is a basic concept in  geology  that describes the dynamic transitions through  geologic time  among the three main  rock  types:  sedimentary ,  metamorphic , and igneous . As the diagram to the right illustrates, each of the types of rocks is altered or destroyed when it is forced out of its equilibrium conditions. An igneous rock such as  basalt may break down and dissolve when exposed to the atmosphere , or melt as it is  subducted  under a  continent . Due to the driving forces of the rock cycle,  plate tectonics and the  water cycle , rocks do not remain in equilibrium and are forced to change as they encounter new environments. The rock cycle is an illustration that explains how the three rock types are related to each other, and how processes change from one type to another over time.

12. SOIL 12 Soil  is the mixture of  minerals ,  organic matter , gases, liquids and a myriad of organisms that can support plant life. It is a natural body that exists as part of the  pedosphere  and it performs four important functions: it is a medium for plant growth; it is a means of water storage, supply and purification; it is a modifier of the  atmosphere ; and it is a habitat for organisms that take part in decomposition and creation of a habitat for other organisms.

13. HYDROSPHERE 13 The  hydrosphere in physical geography  describes the combined mass of  water found on, under, and over the surface of a  planet . This includes water in liquid and frozen forms in ground waters , glaciers, oceans, lakes and streams. Saline water account for 97.5% of this amount.  Fresh water  accounts for only 2.5%. Of this fresh water 68.7% is in the "form of ice and permanent snow cover in the Arctic, the Antarctic, and in the mountainous regions. Next, 29.9% exists as fresh  ground waters . Only 0.26% of the total amount of fresh waters on the Earth are concentrated in lakes, reservoirs and river systems where they are most easily accessible for our economic needs and absolutely vital for water ecosystems.

14. MAJOR WATER BODIES 14 There are four major oceans. They are: Pacific ocean Atlantic ocean Indian ocean Arctic ocean

15. WATER CYCLE 15 The  water cycle , also known as the  hydrologic cycle  or the H 2 O cycle , describes the continuous movement of water on, above and below the surface of the  Earth . The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water , saline water and  atmospheric water  is variable depending on a wide range of  climatic variables . The water moves from one reservoir to another, such as from river to ocean , or from the ocean to the atmosphere, by the physical processes of  evaporation ,  condensation ,  precipitation , infiltration ,  runoff , and subsurface flow. In so doing, the water goes through different phases: liquid, solid ( ice ), and water vapour .

16. OCEANS WATERS AND THEIR CIRCULATION 16 WAVES: waves are caused when winds blowing over the surface of water make the water particles move up and down alternately. Waves travel In the direction of the winds. Tides: Tides  are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the  Moon and the  Sun  and the rotation of the Earth .

17. 17 An  ocean current  is a continuous, directed movement of seawater  generated by the forces acting upon this  mean flow , such as  breaking waves ,  wind ,  Coriolis effect , cabbeling ,  temperature  and  salinity  differences, with  tides caused by the gravitational pull of the  Moon  and the  Sun . Depth contours ,  shoreline  configurations and interaction with other currents influence a current's direction and strength. A deep current is any ocean current at a depth of greater than 100m.

18. ATMOSPHERE 18 The  atmosphere of Earth  is a layer of  gases  surrounding the planet Earth  that is retained by Earth's  gravity . The  atmosphere  protects  life on Earth  by absorbing  ultraviolet solar radiation. By volume, dry air contains 78.09%  nitrogen , 20.95%  oxygen ,  0.93%  argon , 0.039%  carbon dioxide , and small amounts of other gases. Air also contains a variable amount of  water vapor , on average around 1%

19. STRUCTURE OF THE ATMOSPHERE 19 The atmosphere consists of 4 layers: the troposphere, stratosphere, mesosphere, and thermosphere. . The troposphere is the lowest layer of the atmosphere. This is the layer where we live and where weather happens. Temperature in this layer generally decreases with height. The boundary between the stratosphere and the troposphere is called the tropopause . The jet stream sits at this level and it marks the highest point that weather can occur. The height of the troposphere varies with location, being higher over warmer areas and lower over colder areas. Above the In this layer the temperature increases with height. This is because the stratosphere houses the ozone layer. The ozone layer is warm because it absorbs ultraviolet (UV) rays from the sun. The mesosphere is the layer above the stratosphere. The temperature decreases with height here just like it does in the troposphere. This layer also contains ratios of nitrogen and oxygen similar to the troposphere, except the concentrations are 1000 times less and there is little water vapor there, so the air is too thin for weather to occur. The thermosphere is the uppermost layer of the atmosphere. In this layer the temperature increases with height because it is being directly heated by the sun.

20. TROPOSPHERE 20 The  troposphere  is the lowest portion of Earth's atmosphere . It contains approximately 80% of the  atmosphere 's mass  and 99% of its  water vapour   and aerosols .  The average depth of the troposphere is approximately 17 km in the middle latitudes. It is deeper in the tropics , up to 20 km and shallower near the  polar regions , approximately 7 km .

21. STRATOSPHERE 21 The  stratosphere   is the second major layer of Earth's atmosphere , just above the  troposphere , and below the  mesosphere . It is  stratified  in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler higher up and warmer farther down.

22. MESOSPHERE 22 The  mesosphere   the layer of the  Earth's atmosphere  that is directly above the  stratopause  and directly below the  mesopause . In the mesosphere temperature decreases with increasing height. 

23. THERMOSPHERE 23 The  thermosphere  is the layer of the  Earth's atmosphere  directly above the  mesosphere and directly below the  exosphere . the thermosphere begins about 85 kilometres above the Earth. This layer contains electrically charged particles called ions.

24. EXOSPHERE 24 The  exosphere is a thin, atmosphere-like volume surrounding a planetary body where molecules  are gravitationally bound to that body, but where the density is too low for them to behave as a gas by  colliding  with each other. 

25. Air  is the  Earth 's  atmosphere . It is the clear  gas  in which living things live and  breathe . It has an indefinite shape and volume. It has no color  or  smell . It has  mass  and  weight . It is a  matter  as it has mass and weight. Air creates  atmosphere pressure . There is no air in the vacuum  and  cosmos . Air is a  mixture  of 78.03%  nitrogen , 20.99%  oxygen , 0.94%  argon , 0.03%  carbon dioxide , 0.01%  hydrogen , 0.00123%  Neon , 0.0004% helium , 0.00005%  krypton  and 0.000006%  xenon . There are also small amounts of other things. The degree of hotness or coldness of air surrounding us is called air temprature . Atmospheric pressure  is the force per unit area exerted on a surface by the weight of air above that surface in the  atmosphere of Earth  . Humidity  is the amount of  water vapour  in the  air . 25 AIR TEMPRATURE,PRESSURE AND HUMIDITY

26. BIOSPHERE 26 The  biosphere  is the global sum of all ecosystems . The biosphere is postulated to have  evolved , beginning with a process of  biopoesis  (life created naturally from non-living matter such as simple organic compounds) or  biogenesis  (life created from living matter), at least some 3.5 billion years ago.

27. BY SWAROOP RAJ 27