Three fourth of the Earth surface is covered with Water.
Water is found in Puddles, Ponds, Rivers, Lakes, Oceans, Underground, Glaciers ( Ice), Air ( Water Vapor)
Why sea water cannot be used for consumption?
· The available water content in the sea is 97.4%
· It has very high salt content and hence cannot be used for the consumption.
Where do we get fresh water for consumption?
· Fresh water are nothing but the rain water
· Rain water are stagnant in Ponds, Lakes, flow down from mountains as rivers, fresh water is available as frozen glaciers and polar ice cap.
· Only 0.01% of water on Earth is available for consumption
· The main source of fresh water is Ground Water
Importance of Water:
· About 70% of human body consist of water.
· All the life processes such as digestion of food, absorption of nutrients to various part of the body, getting rid of body waste requires water
· We take in water through food ( Through Fruits, Vegetables and as such water), We lose them in the form of urine, sweat, exhaled air.
· Water helps us to control our body temperature.
Water in Plants:
· Water is required for germination and growth.
· It helps to transport nutrients from soil and food from leaves to different parts of the plants.
· Plants use Carbon di oxide from air, water from the soil, in the presence of sunlight it makes food. This process is called as Photosynthesis
· Plants take in water from the soil through roots
Other uses of water:
· Water is essential for cooking, washing
· Water in dams is used to generate electricity
· Water is used extensively in agriculture and industries\
· Water is used as medium of transport
· Water is home for many aquatic plants and animals
What are the three states of water?
· The three states of water are Solid ( Ice cube), Liquid ( Water ), Gas (Steam)
· In Nature, water exist in
· Solid state in Glaciers
· Liquid in rivers, lakes, seas, oceans
· Gaseous state as water vapour in air
How can the states of water be achieved?
States of water can be achieved by changing the temperature. Freezing and Melting
What is Evaporation?
When Ice is heated, it melts quickly to form water. This is known as melting of ice. When the liquid water is heated up, it changes to water vapor (Gaseous state) . This process is known as Evaporation
What is Condensation?
When water vapour is cooled, it changes back to liquid form. This is known as condensation
Change of State of Water:
· To convert the state of water into another, temperature is the physical quantity that needs to be reduced.
· Evaporation occurs at all temperature.
· Clothes are dried in the sun because evaporation occurs at faster rate under sunlight
There is a moist air in the container, how can we reduce the quantity of water in the air?
This can be done in two methods.
1. Keep the container under the Sun, so that the moist air will be evaporated due to sunlight
2. Silica gels can be placed inside the container; it will absorb the moist air in the closed container.
Define Water cycle?
The constant circulation of water from Earth to the atmosphere and back to Earth again is known as Water cycle.
Explain in simple Water Cycle?
· Water in the Seas, Rivers, lakes, Pond evaporates due to the heat of the sun.
· Plants give out large amounts of water during transpiration through the stomata present in the leaves
· Water vapour rises up
· The air in the atmosphere is cooler
· In the atmosphere, water vapour condenses to form water droplets.
· The water droplets join together to form clouds
· As clouds get cooled, water drops become bigger
· When clouds become too heavy, they fall on Earth as rain. This process is called as Precipitation.
· Sometimes when water in the atmosphere is too cold, they freeze and fall down as Hail/Snow
· Water cycle is the main source for ground water, and they get frozen on mountains
What are the various sources of water?
The various sources of water are Rainwater, Ground water
Write a short note on Ground Water?
· When rainwater runs off the surface forming streams and rivers, some water passes through the soil into the non-porous rock. This is called as Ground water/ Underground water
· Level of the underground water is called as Water table
· Ground water in some places come out naturally over the surface forming the natural springs
Is ground water safe for drinking?
· Groundwater passes through soil, it gets filtered by various layers of rock and sand.
· It is almost free of suspended impurities but contain dissolved salts, germs
· Boiling of water helps in the removal of these impurities and germs and make the water suitable for drinking.
How is ground water Obtained?
· Ground water is usually obtained by digging wells/ tube wells
· Overuse of the ground water is causing the water table level to decrease in cities and towns
· Write a short note on Surface water?
· Rainwater that runs off on the surface of Earth to form rivers, streams, lakes, rivers are called as Surface water
· It contains dissolved salts, suspended impurities, germs
Why surface water is not safe for drinking?
· Sewage from cities, harmful substances from factories are discharged into rivers.
· This pollutes the water, making it unfit for the consumption
· Water from rivers need to be cleaned and then supplied to homes in towns and villages.
Why sea water is unfit for consumption?
· Rivers ultimately flows into the sea.
· Sea water contains large amount of dissolved salts, so it is unfit for consumption, Irrigation and Industrial purposes
Difference between Ground water and Surface Water?
| Ground water | Surface water |
| Water that is trapped/ found on the underground of Earth is called as Ground Water | Rainwater that flows on the surface of Earth to form the streams, rivers, lakes are called as surface water |
| Ground water is less contaminated than surface water | Surface water is more contaminated |
| Ground water is not exposed to sunlight | Surface water is exposed to sunlight and evaporation takes place |
| Ground water has constant temperature | Surface water has change of temperature according to their surroundings |
Write a short note on Droughts?
· When the monsoon fails, summers extend leading to severe shortage of water
· Rivers and ponds are dried up, soil becomes dry since more water is lost due to evaporation.
· Plants loses its water extensively due to transpiration; crops do not grow. This condition is called as drought
Which states in India are prone to droughts?
Some parts of Rajasthan, Gujarat, Madhya Pradesh are prone to drought
What are the effects of Drought?
· Shortage of water leads to shortage of food for humans and livestock
· Since the land is dry, fertile topsoil is blown away by winds. This is called as soil erosion. This leads to loss of fertile lands
· When crops are not grown, it leads to shortage of grains, fruits, vegetables, milk, meat etc
· When monsoon fails for several years, it leads to severe shortage of food, water and leads to a condition called as Famine.
· People may die due to the spread of diseases and lack of food
Define Flood?
During Monsoon, when it rains heavily, often the water rise above their banks, flow into nearby land. This condition is called as Flood.
What is the effect of the flood?
· Flood causes the damage to crops, roads, houses
· There may be shortage of food, drinking water and shelter.
· Water logging last for several days, lead to the outbreak of diseases such as Cholera, Malaria, Dengue
· Electric lines, water supply, communication networks also get affected.
· When there is severe flood, people, animals may die due to drowning, hunger, thirst and diseases
What is cyclone? Which state in India are prone to Cyclone?
· Cyclone is very strong wind along with heavy rain.
· Strong wind causes high waves called Tidal waves in sea
· Cyclone causes flooding in coastal areas
· Andhra Pradesh, Assam, Bihar, Gujarat, Maharashtra, Odisha, Tamil Nadu, West Bengal are prone to cyclones
What is conservation of water?
Conservation of water means wise and careful usage of water and maintain the quality of water
List few methods to conserve water?
· Avoid wastage of water
· Recycle water whenever possible
· Planting more trees increases the absorption of water by the soil and it increases the water table
· Reduce water pollution by treating sewage and factory waste before disposing them
· By building dams, we can store excess water and prevent flooding
· Rain water harvesting can be done
Write in short about the Rainwater harvesting?
· Storing of rain water in storage tanks and directing rain water to pits ( near bore) is called as Rain water harvesting.
· Most of the rain water drained directly into the lakes and rivers due to cutting of trees for construction of roads and buildings
· Rainwater harvesting can be done in two ways
· Rainwater falling on rooftop of building is directed towards the storage tank ( can be used in gardening)
· Rainwater flowing into roadside drains is allowed to flow deep into pits, so it adds to the groundwater
Useful links: