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SAI INTERNATIONAL SCHOOL
                                                        Class-6

                                                    Lesson Note
                                                  Subject-Physics
                                      Ch.- Water: The Life-giving Liquid

                                            Subtopic- States of Water


        States of water:
              In nature, water occurs in all the three states of matter, solid (ice or snow), liquid (water)
               and gas (vapour).
              This three states of matter is inter-convertible.

        Solid state of water:
              When liquid water is cooled to 0°C (zero degree celsius) it changes to Ice.
              The process by which a liquid changes to its solid form on cooling is known as freezing.
              The temperature at which a liquid changes to its solid form is known as freezing point.
              The freezing point of water is 0°C.

        Gaseous state of water:
              When liquid water is heated to 100°C it begins to boil and changes into water vapour.
              The process by which a liquid changes to its gaseous form on heating is known as
               vaporization / boiling.
              The temperature at which a liquid changes to its gaseous form is known as boiling point.
              The boiling point of water is 100°C


        Liquid states of water:
              On cooling the water vapour, it gradually changes back to liquid water.
              The process by which a gas changes to its liquid form on cooling is known as condensation.
               And, on heating the ice, it changes to liquid water.
              The process by which a solid changes to its liquid form on heating is known as melting.






















        Note:
        The process of conversion of water from its liquid state to Vapour state, below its boiling point is
        known as evaporation.
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