Earth as a planet

Cards (62)

  • The earth is the third planet from the sun and the fifth-largest planet in the solar system
  • Earth is the only planet which supports life
  • 70 per cent of the earth's total area is covered by water
  • The family of the sun is called the Solar System
  • Members of the solar system
    • Planets
    • Satellites
    • Asteroids
    • Comets
    • Meteorites
  • The planets in order of their distance from the sun are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune
  • Shape of the Earth
    • Bulges slightly at the centre
    • Flattened at the poles
  • In the olden days, the earth was considered to be a flat disc with steep edges
  • Aryabhatta, the 5th century Indian astronomer and mathematician, believed in the round shape of the earth
  • Pythagoras, the 6th century Greek philosopher, said the earth was spherical in shape
  • Today, we have convincing evidence to prove that the earth is spherical in shape
  • Proof that the Earth is Spherical in shape
    • Sighting of a ship
    • Bedford Level Experiment
    • Pole Star
    • Satellite Pictures
    • Lunar Eclipse
    • Circular Horizon
    • Sunrise and Sunset
    • Circumnavigation
  • The earth is said to be an Oblate Spheroid, which means it bulges at the equator and is flattened at the poles
  • The earth belongs to the Solar system and all planets in this system are spherical in shape
  • Features that make Earth habitable
    • Distance from the Sun
    • Temperature
    • Atmosphere
    • Water
  • The earth is at an optimum distance from the sun, which makes life possible
  • The earth has an average temperature of 17°C which is suitable for life to exist
  • The earth's atmosphere is a mixture of gases like nitrogen, oxygen, carbon dioxide, helium and argon
  • Ozone in the earth's atmosphere absorbs the harmful ultraviolet rays of the sun
  • The earth's atmosphere prevents loss of heat from the earth's surface and helps to keep the earth warm
  • 70 per cent of the earth's surface is covered by water
  • Water cycle
    1. Evaporation from oceans
    2. Transpiration from plants
    3. Condensation
    4. Precipitation
  • The self-regulating and self-sustaining structural and functional unit of the biosphere is called the Ecosystem
  • The ecosystem depends upon the sun for its energy
  • The atmosphere receives heat from the sun by solar radiation and loses heat by earth's radiation. In this way a balance is maintained
  • Gases in the earth's atmosphere
    • Nitrogen
    • Oxygen
    • Carbon dioxide
    • Helium
    • Argon
  • Ozone present in the earth's atmosphere absorbs the harmful ultraviolet rays of the sun
  • The atmosphere also prevents loss of heat from the earth's surface and helps to keep the earth warm
  • Earth is a watery planet with 70 per cent of the earth's surface being covered by water
  • Ecosystem
    The self-regulating and self-sustaining structural and functional unit of the biosphere
  • Examples of ecosystems
    • Pond
    • Lake
    • Desert
    • Grassland
    • Meadow
    • Forests
  • There is an exchange of materials and energy within the ecosystem as well as between adjoining ecosystems. They are all interconnected and hence, interrelated
  • Biosphere
    The part of the earth's terrestrial system-including air, land and water-in which life develops and where life processes in turn get transformed
  • Water can absorb enormous amount of heat without causing much change in its temperature
  • But for the tremendous amount of water on the earth, far greater day and night temperature variations would exist
  • Lithosphere
    The solid crust of the earth
  • Due to the weathering of the rocks, the surface of the earth has been formed, which provides soil layer essential for supporting plant life
  • Soil also provides various nutrients necessary for the growth of plants, which in turn support all forms of animal life directly or indirectly
  • Biosphere
    The narrow realm of contact and interaction between the atmosphere, lithosphere and hydrosphere
  • Biosphere provides all the necessities for all the species living on earth, i.e., light, heat, water, food and habitats