WATER | SPEED NOTES | SCIENCE | CBSE | CLASS 6

CBSE Class–VI

Subject Science

Revision Notes

CHAPTER – 14 Water

WATER : NATURAL GIFT Water is an inexhaustible or renewable natural resource. Three -fourths ofthe earth's surface is covered withwater. Nearly 70% ofour body ismade up ofwater and therest is solid matter. Water is essential forlife. Water which is fit forhuman consumption isknown as water.

Only 2.6%of total wateris fresh water. Only 0.01% of the total water reaches humans and animals. Fresh water or Potable SOURCES OFWATER

Rain water Ground water Surface water Rivers andstreams Lakes andpounds Sea water

STATES OFWATER water on theearth exists inthree states :solid , liquid and gas.

WATER ANDITS FORMS Ice is the solid state of water. Water is theliquid state ofwater. Vapour or steam is the gaseous state of water.

·Water Cycle: The cycle of processes bywhich water circulates between the earth's oceans, atmosphere, andland, involving precipitation as rain andsnow, drainage instreams and rivers, and return to theatmosphere by evaporation and transpiration.

Water Conservation: Itis the wiseand judicious useof water. Ways of conserving water: Get all leaking taps repaired. Use a bucket fortaking bath instead of a shower. Collect rainwater and use it for gardening and recharging ground water. Wash yourcycles, cars, etc.with a bucket of water instead of pipes. Instead of washing the floor usea mop.

Importance of Water: Digestion of food takes place in the stomach when food is mixed with water. Important medium for the transportation of food, oxygen and carbon dioxide in the body. Water is usedto produce electricity. Water is essential for the germination of seeds. Waterhelps in maintaining the body temperature. Excess of water: When it rains or snow, some of the water is retained by soil. Its caused flood. It effects bydamage property andendanger the lives of humans andanimals. Rapid run-off causes soilerosion.

Lack of water: It is the lack of sufficient available water resources to meet water needs within a region. Itcause drought likecondition. It effect by acute watercrisis, crop failure, loss of lifein all formsdue to starvation.

Rainwater Harvesting: Method of collecting rainwater and storing it for useduring scarcity. It canbe used forseveral purposes including drinking, washing, gardening, flushing, etc.

Water vapour getsadded to airby evaporation andtranspiration. The water vapour in the aircondenses to formtiny droplets ofwater, which appear as clouds. Manytiny water droplets come together andfall down asrain, snow orhail.

Rain, hail andsnow replenish water in rivers, lakes, ponds, wells andsoil. Excessive rainsmay cause floods while lack of it forlong periods maycause droughts. Theamount of usable water on earthis limited soit needs to be usedcarefully.