Grade 4 | Science | Water, Our Environment, Olympiad, CBSE, ICSE, SOF, ITO
Water is essential for our survival. Our body primarily consists of water. Almost 3/4th of earth's surface is covered with water.
Water has following properties:
Sources of water: Common sources of water are rainwater, wells, tube wells, rivers, oceans, canals, lakes and handpumps.
Movement of water from and below earth's surface to air and then back to earth's surface is called Water cycle.
Water cycle occurs as the cycle of the following processes :
Evaporation: Water evaporates from earth's surface and water bodies due to the heat of the sun. Water is converted into vapours. This process is called evaporation. Vapours are light and they rise in the air.
Condensation: Condensation is the process by which vapours cool down to liquid.
Precipitation: Many small droplets of water combined to form big drops. These drops are heavy and come down as rain, sleet, snow, or hail. This process is known as precipitation.