Water Basics: Sources, Uses, and the Water Cycle

The chemical reactions in all plants and animals that support life take place in as water medium. Water not only provides medium to make these reactions possible but is itself an important reactant or product of these reactions. Water is thus an important universal solvent. It consists of 2 hydrogen atoms and one oxygen atom which are held together by covalent bonds. Oxygen is more electronegative than hydrogen molecules. Hydrogen is positively charged and oxygen is negatively charged. Thus it can dissolve and dissociate most of the compounds. Positive part will be attracted towards oxygen and negative part of the compound towards hydrogen.

Water is an essential molecule required by living beings for all processes. Clothes need to be washed properly to remove dust and dirt which is done by using water and detergent. Huge amount of water is required to wash clothes properly.
A very little amount of water is required for bushing, cooking and drinking as compared to washing clothes.

Furniture is the object used in various human activities especially in the households like beds, chairs etc. These objects are mostly made up of woods or glasses. Water is not used in making the furniture.

Water is present as marine water or fresh water. Marine water is that which consists of large amounts of salts and minerals thus known as saline water. Freshwater does not consist of salts. Rivers, ponds and lakes are freshwater sources and ocean is a source of marine water.

About 71% of the earth’s surface is covered with water which is present in various water bodies like rivers, oceans, seas, canals, lakes, etc. Oceans cover the major part of the earth.

Dam is a man-made construction which is built to retain water, to manage or prevent water inflow into specific land regions and also to produce hydroelectricity. It is not a natural source of water.

About two-thirds or 71% of the area of the earth is covered by water. Water is present on the earth’s surface in the form of various water bodies like oceans, rivers, seas, canals, lakes, rivers, etc. Major part of the water is present in oceans.

Water required for domestic purposes in various households is supplied from water treatment plants where water is purified, after which this treated water is transferred to domestic areas using water pipes or a network of pipes.

Water present in sea largely consists of salt thus known as saline water which is not fit for human consumption.

Spring is a type of season which comes at the end of winter season and before the starting of summer season. It cannot be a source of surface water.

Evaporation is a process in which water in its liquid form is changed into gaseous form by the process of boiling. Water present on the earth’s surface in various water bodies changes into water vapours by the process of evaporation and thus, gets evaporated from the earth’s surface into the atmosphere.

Transpiration is the process of loss of water in the form of vapours from the exposed parts of a plant. It takes place mainly through stomata which is present in the leaves.

Water present in natural water bodies on the earth's surface gets evaporated to vapour form and this evaporation takes place by the heating effect of sun rays.

Water can get evaporated easily if direct sunlight is provided to the water body, but if water is present in the shade, where there are no direct sun rays falling, warm air is required to heat the water so as to evaporate it into vapours.

During winter mornings, the exposed surface cools by radiating its heat. Thus, water vapour present in the atmosphere condenses, resulting in the formation of water droplets on the exposed surfaces. These water droplets are known as dew. Dew is formed very easily on grasses and leaves of plants.

Condensation is process in which water vapours present in atmosphere are changed or cooled down to form water droplets. These water droplets combine together to form clouds. Thus clouds are composed of millions of little droplets of water.

Mist is the formation of water droplets in air from water vapours by the process of condensation, near or in contact with the earth’s surface during the winters. Mist is different from fog only by visibility. Mist does not reduce visibility as much as fog does. 

Evaporation takes place when there is heat or sunlight available causing the increase in temperature which results in the formation of water vapours. At noon, maximum rays of sunlight reach the earth's surface causing increase in temperature. Thus maximum rate of evaporation takes place not noon.

Water drops appear on the outer surface of glass containing cold water. The cold surface of the glass containing cold water cools the air around it, and the water vapour of the air condenses to form water droplets on the surface of the glass. Thus, it is a process of change of gaseous state into liquid state.

Water is very essential for all life processes on earth. Water is continuously being recycled by the processes of evaporation, condensation to form clouds, precipitation to form rain. Thus water once evaporated again gets recycled on the earth's surface in the form of rain; therefore the ultimate source of water in earth is rain.

All the choices given i.e. evaporation, transpiration and condensation are natural phenomena. Crystallization is a process of formation of crystals by boiling a liquid and then cooling it until gets solidify into a crystalline solid either by natural process or artificially. Ice crystals are formed naturally by the freezing of water. So crystallization is an artificial process.

Water is present below the earth's surface as an important resource to be stored and preserved and do not get easily evaporated. This water below the earth's surface is known as groundwater which forms the water table.

Water present below the earth's surface as ground water can be fetched by hand pumps which are manually operated to extract water from underground.

Rain water in mountains flows down in the form of streams and rivers. Stream is a body of water with a current confined within a bed and stream banks flowing down from mountains. Rivers is a natural water source flowing towards an ocean, sea or another river originating from mountains.

Open wells are constructed to fetch water present deep inside the earth’s surface in the water table where water, known as groundwater, is stored and preserved for various life processes.