1st Class EVS Weather, Air and Water Air, Water and its Resources

Air, Water and its Resources

FUNDAMENTALS

•                        Air is present everywhere. It is mixture of different gases like nitrogen, oxygen, carbon - dioxide etc.
•                        Living things need air to breathe.
•                       Air cannot be seen with our naked eyes. Air has no colour, taste or smell.
•                        Air occupies space. Air was weight, e.g. When football is filled with air it has weight, wheels of car, buses, cycles etc.
•                       Air is necessary for life. Without air, life is not possible.
•                      The moving air is called wind. When the winds blow gently, it is called breeze. Motion of air from sea to land is called sea breeze and land to sea is called land breeze. A breeze is very pleasant. All the living being enjoys the gentle wind.
•                       When the wind blows strongly, it is called storm. A storm is very harmful. It can uproot trees, damage plants, break window panes and blow off the roof of huts. Storm are of different types - dust storm, snow storm, rainstorm etc.
•                     Wind is used for many purposes such as to dry clothes, fly kites, fill hot air balloons, sail boat, run windmills, generate electricity etc.
•                     Water is a natural resource. All living organisms need water. The sources of water are mainly oceans, seas, rivers, lakes, ponds, streams, waterfalls etc.
•                      Life is not possible without water.
•                      Water is found in three forms - solids, liquids and gases. Water changes from one state to another due to change in temperature.
•                   Water is a liquid. Liquid water has no fixed shape. It takes the shape of the container. Ice (solid) has a fixed shape. It melts into liquid, when kept in warm place. When heated water changes into water vapour.
•                       Soluble things are those things that dissolve, when mixed with water. For e.g., sugar is soluble in water.
•                     Non - soluble things are those things that does not dissolve in water e.g., oil does not dissolve in water.
•                     Things that stay on the surface of liquid without sinking is called floating.
•                      If an object weighs more than volume of water, it is denser and will sink or otherwise it will float.
•                      Evaporation is the change of state from a liquid to a gaseous form by heating.
•                    To mix completely in water is said to be completely dissolved in water.
•                 Water is used for various purposes such as drinking, washing, cleaning, and cooking food, bathing, and watering plant, construction of building, production of electricity.
•                      Water is very precious. We should not waste it. Water should be conserved by various methods such as by reducing wastage of water, recycling of waste water etc.