Why Can’t We Drink Sea Water?
We all need food, water and air to live. A major part of our body cells is made of water. If a person does not drink water required to keep the balance of water inside the body, the resultant `dehydration’ may kill him.
There is more water than land on the surface of the earth. But the huge amount of the sea water on earth cannot be used directly for drinking by us. Not only because it will taste salty. but also because it will have a bad effect on our body.
In our body, a natural process called ‘osmosis’ helps liquids pass through the thin walls of body cells. Normally, the water that goes to the cells is lighter than the water that is already present inside them, and so it passes through the cell walls and enters the cells. But if salt water reaches these cells the water from inside the cells joins this salt water instead of allowing it to enter the cells. Thus the cell becomes even drier by losing water. A thirsty person after drinking salt water actually makes his body thirstier. People travelling on a ship have to carry their drinking water with them because even if they are surrounded by water from all side they cannot drink it to quench their thirst!