Saving Water

　　The world is not only hungry, hut also thirsty for water since nearly 75 % of the earth's surface is covered with water Man can only drink -and use the other the fresh water that comes from rivers, lakes And we cannot even use all of that, because some of it is in ihe form of icebergs and glaciers

　　However, as Hut our need for water is increasing rapidly almost day by day A limited water supply would have a bad effect on agriculture and industry Did you know that to produce a single ton of steel, il takes about 91*000 liters of water?

　　We all have to learn how to stop wasting our precious water Experiments have already been done in this field, but only on a small scale the systems are as important as the spacecraft.