Sources of Water and its Purification

• Water is one of the essential things required to sustain life on Earth.
• It is found in all three states on Earth—ice, water and water vapour.
• Rain is the main source of water.
• Sea, ocean, lake, and rivers are examples of natural sources of water.
• Water is present in both fresh and saltwater sources.
• Examples of freshwater sources are lakes and wells, whereas seas and oceans are the sources of saltwater.

Sources of Water

Question 1:

How Do We Measure the Water We Receive in Our Houses?

Answers:

• Water supplied in different localities is measured using a water meter.
• The city area generally receives around 400 to 600 litres of water for each house.
• In the village area, the water supply through pipelines is about 300 to 400 litres.

Question 2:

Why Is Ocean Water Salty and Not Suitable for Use?

Answers:

Water in the ocean is filled with salts and minerals, which makes it salty and unsuitable for use.

Question 3:

What Happens to the Rainwater After It Reaches the Land?

Answers:

• The rainwater gets infiltrated into the soil and gets stored in the aquifers.
• Aquifers are underground storage spaces found in the deep layers of soil.
• Some amount of rainwater gets drained into the rivers and oceans.

Question 4:

Does the Total Amount of Water on the Earth Remain Constant?

Answers:

• Yes, the total amount of water on the Earth remains constant. The water only changes its forms through the water cycle.

• So, when the lakes or ponds dry during the summer, the water converts into water vapour. It helps in the formation of clouds.
• The same water then comes down as rain on the Earth’s surface.

Question 5:

What Is the Purpose of Building Tall Water Tanks in Our Surroundings?

Answers:

The municipal authority pumps the purified water into tall water tanks. These tanks are tall because they can supply water by gravity to a larger area in less time. It is an easy way to supply water.

Ways to Conserve Water

Question 1:

Why Does Lightning Make Noise?

Answers:

• The loud noise that we hear during lightning is due to the collision of clouds with each other.

Question 2:

Why Do We Experience Hail Storms or Snowfall Instead of Rainfall?

Answers:

• When the temperature of the surroundings decreases sufficiently to convert water drops into snow or ice balls, rainfall occurs in the form of snowfall or hailstorm.

Monsoon Weather

Question 1:

We Receive Plenty of Water Daily in Our House, So Why Should We Conserve It?

Answers:

• Out of the whole water available on Earth, we can use only 1% of it.
• Hence, looking at the availability and rate of water consumption, it is necessary to be used judiciously and conserved.Hence, looking at the availability and rate of water consumption, it is necessary to be used judiciously and conserved.
• Otherwise, a situation of water scarcity may arise.

Question 2:

How Do Fertilisers From Agricultural Lands and Smoke From Factories Pollute the Water Bodies?

Answers:

• Fertilisers contain non-biodegradable waste which do not decompose and keep accumulating in the soil. They are drained off to water bodies during rain, leading to water pollution.
• The smoke released from factories contains harmful gases which get mixed with rainwater and reach the Earth’s surface during rainfall. Ultimately when this rainwater is drained into water bodies, they get polluted due to toxic substances.

Pure Water

Question 1:

How Is Water Purified in the Purification Plant?

Answers:

Water is purified in the purification plant by the following steps—

• The water is vigorously bubbled with air.
• Some chemicals (like alum) are added to the bubbled water.
• The water is then gently and continuously stirred.
• The water is left undisturbed for some time, leading to settling contaminants at the bottom.
• The water separated from impurities is then filtered and disinfected using chlorine or UV rays.

Question 2:

What Is Alum Used for? What Happens When We Add Alum to Muddy Water?

Answers:

• Alum is used for purification of water.
• Alum particles are capable of attracting mud or dust particles in the water.
• Once it is dissolved in water, it attracts the mud particles, and they settle down at the bottom of the container after some time.

Question 3:

Why Is the Water Dripping From the Rocks in the Mountains Pure in Nature and Taste Good?

Answers:

• The water dripping from the rocks in the mountains comes from the melted glaciers.
• Glaciers are the source of freshwater; hence the dripping water tastes good.
• Moreover, when water passes through multiple layers of rocks or soil, it gets filtered naturally due to the removal of contaminants.
• Thus, the water is automatically purified.