Occurrence Of Water

Water of Class 7

The distribution of water over the earth’s surface is not uniform throughout. Water is available in nature mostly in Free State and to a somewhat lesser extent in combined state.

Water exists in free in all the three physical states namely solid, liquid and gaseous states:

  • Solid State: Certain regions on earths like high peaks of mountains,  polar regions in Antarctica and the arctic circle contain water as snow or ice.  In these places, water exists in solid state due to the very low temperatures prevailing in those regions.
  • Liquid state: It is the most common state in which water exists.  Most of the liquid water is found in oceans and seas.  Apart from this, liquid water is also found in rivers, lakes, streams and other water bodies.  Water available in the above sources is called surface water.  Water present in oceans and seas contain appreciable proportions of dissolved salts, predominantly sodium chloride.  The presence of these salts imparts salty taste to water and this water is hence called saline water.
  • Gaseous State: In gaseous state, water exists as water vapour in the atmospheric air.  Clouds, fog, mist etc., contain water vapour in condensed form.
    Water exists in combined state in the form of body fluids in the body of living beings. Water is also present in combined state in hydrated crystals like CuCO4.5H2O, FeSO4. 7H2O etc.

NCERT SOLUTIONS FOR CLASS-7 SCIENCE (Science for grade-7 NCERT solutions)

Chapter 1 - Nutrition in Plants

Chapter 2 - Nutrition in Animals

Chapter 3 - Fibre to Fabric

Chapter 4 - Heat

Chapter 5 - Acids, Bases and Salts

Chapter 6 - Physical and Chemical Changes

Chapter 7 - Weather, Climate and Adaptations of Animals to Climate

Chapter 8 - Winds, Storms and Cyclones

Chapter 9 – Soil

Chapter 10 - Respiration in Organisms

Chapter 11 - Transportation in Animals and Plants

Chapter 12 - Reproduction in Plants

Chapter 13 - Motion and Time

Chapter 14 - Electric Current and Its Effects

Chapter 15 – Light

Chapter 16 - Water: A Precious Resource

Chapter 17 - Forests: Our Lifeline

Chapter 18 - Wastewater Story

 
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