1. Nature, Properties, and Distribution of Water

The water molecule is composed of two hydrogen atoms attached to an oxygen atom with a V-shape formation and an angle of 105° between the hydrogen atoms. It has a slightly negative charge at the oxygen end and a slight positive charge at the hydrogen end. This makes the water molecule polar, i.e., having poles like a magnet. This property makes water molecules attract each other, thus giving it unique properties such as rising in capillary tubes, plant roots, and blood vessels against gravity. Water has a high latent heat enabling it to absorb large quantities of heat before a rise in temperature; this enables the waters of the oceans to affect the earth’s temperature in a gradual manner. Water is an important solvent. Water forms about 71% of the earth’s surface, but most of it is saline. Freshwater which is required for domestic and industrial use, and for agriculture forms only about 2.5%. Water is distributed in the atmosphere as clouds; on the earth’s surface as oceans, seas, rivers, and lakes; and underground.