Science 2 Marks Questions

The Earth is covered by water, however, almost 97% is salt water found in the oceans. We cannot drink salt water or use it for crops because of the salt content. We can remove salt from ocean water, but the process is very expensive.

Plants need water to obtain nutrients from the soil to prepare food and also transpiration rate is high in summers. So, they die from lack of nutrients.

1. In filtration: The water from rain, rivers, lakes and ponds seeps through the soil and fills the space below the ground. The process of seeping of water through the soil is called infiltration.

2. Aquifer: Some places groundwater is stored between layers of hard rock. This is called aquifer. Water from aquifers is pumped and taken out through hand pumps and tube wells.

The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration.

Water drawn from under the ground gets replenished by seepage of rainwater; the water table is not affected as long as we draw as much water as is replenished by natural processes, and however it may go down if the water is not sufficiently replenished.

A majority of farmers in India depend upon rains for irrigating their crops. Irrigation systems such as canals are there only in a few places. Even these systems may suffer from lack of water due to erratic rainfall. Therefore, farmers have to use groundwater for irrigation. Population pressure on agriculture forces increasing use of groundwater day by day. This results in depletion of water table.

Precipitation (rain) is a natural process and is a part of natural water cycle. It replenishes all the natural resources of water like ponds, lakes, river and finally oceans and seas too.
When we say utilisation of rainwater, we mean that rain in a particular area.
Yes, it is not properly utilised as most of the water is run off as surface water to the rivers and goes to oceans.
We can harness/ harvest this water to local waterbodies like ponds, lakes and groundwater by proper planning as it is being done in some districts of Rajasthan successfully.

3. Increasing population create demand for construction of houses, shops, offices, roads and pavements.

2. This decreases the open areas like parks and playgrounds.

1. Which inturn decreases the seepage of rainwater into the ground.

4. This result in depletion of water table and creates scarcity of more water.

Rainwater harvesting is defined as the method of collecting rainwater on roof-tops and directing it into the ground so as to raise the water table or use for household purposes.

We face shortage of water mainly because water is not evenly distributed by the nature on the earth. Some places such as North East India get so much rains, so that it gets flooded almost every year. On the other hand, Thar desert in Rajasthan may get rains rarely in the monsoon season. This uneven pattern of rains causes water scarcity in India at some places.

Instead of letting rainwater run-off into the sea, it can be used to recharge ground water. This is known as rainwater harvesting.
Rainwater harvesting can be used to raise the water table in arid areas. It can also be used to create water storage areas.

Water is a precious source because all our daily activities are carried out with the help of water only. Water is found everywhere but not everywhere it is drinkable/ usable. Though the seas have no lack of water but still we can't drink or use it anywhere. Water helps in nourishment of animals and plants. We can't live without water and because it is scarce, that’s why water is precious.

Drip irrigation is a technique in which water is supplied drop by drop near the plant roots through small openings called drippers. This method avoids wastage of water and is a very economical way of irrigation.

The factors responsible for the uneven distribution of water over the globe are the uneven rainfall patterns and uneven climatic conditions.

Water is used by all the industries. Almost everything that we use needs water somewhere in its production process. The number of industries is increasing continuously. Water used by most of the industries is drawn from the ground.

Farming, which typically requires huge quantities of water, can also benefit from good water management. Drip irrigation is an economical way of using water. This technique involves the use of tubes to deliver water straight to the base of a plant, where it is taken up by the roots.

Yes, scarcity of water affects every form of life. It leads to crop failure, fall in production and ultimately loss of life due to starvation.

Plants need water to absorb nutrients from the soil and make their food. Without water, plants would die, and greenery would be lost. This, in turn, would mean the end of all life on the earth, because without plants, there would be no food, oxygen or rainfall. There would also be many other problems.

The three forms of water:

1. In nature are snow (solid), water (liquid) and water vapour (gas).
2. At home are ice (solid), water (liquid) and steam (gas).

The evaporated water above the earth surface is carried away by warm air. As the warm air moves higher from the surface of the Earth, it starts to cool down. It is because the water vapour present starts to condense to form tiny water droplets. These droplets float in the air and form cloud.

The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration. The groundwater thus gets recharged by this process. At places the groundwater is stored between layers of hard rock below the water table. This is known as an aquifer. Water in the aquifers can be usually pumped out with the help of tube wells or hand pumps.