Chapter 17: Water-A life giving Liquid page 243

Lesson 18/ Chapter 17: Water-A life giving Liquid page 243

Water - A renewable Resource

Water Resource

• More than 70% of the human body is composed of water.

• The human body requires 2-3 Litres of water everyday for proper functioning.

• Water helps in digestion of food and removal of undigested food from the body.

• It also helps regulating the body temperature.

• Plants and also animals also needs water for their metabolic functions. It also serves as natural habitats for aquatic species.

OTHER USES OF WATER AS FOLLOWS:

• Essential for agriculture, photosynthesis, and seed dispersal

• Used to manufacture medicines and chemicals

• Used to generate electricity

• Water sports such as swimming, surfing,

• Also effective used for healing purposes in the treatment of certain disorder

• Domestic purposes such as drinking, cooking, washing, cleaning and gardening

Forms of Water:

• Water in liquid(L) form, it is present in the lakes, rivers, ponds, oceans, etc.

• Ice is the solid(S) form of water. It is seen in the form of glaciers, snow-covered etc

• Water in the form of water vapour(G) is present in the air around us.

• Heating or cooling will change its state. Ice starts melting at 0 oC(melting point). Freezing point of water is 0 oC

• Boiling point of water 100oC

• processes: melting(S-L), freezing(L-S), evaporation(L-G) and condensation(G-L),

QUIZ TIME

Multiple Select

The three forms of water are as follows;

• ice

• steam

• gel

• lake

Multiple Select

Which are true about water- a renewable resource?

• 30% in the human body

• our body need 3 litres of water everyday

• used for plants and animals for metabolic functions

• it helps for digestion and removal of undigested food from the body.

Multiple Select

Which is not a natural sources?

• light

• water

• soil

• coal

Multiple Choice

Water molecule is made up of 2 atoms of______ and 1 atom of ________

• oxygen, hydrogen

• hydrogen, oxygen

• hydrogen, carbon

• carbon, nitrogen

Multiple Select

Check the other uses of water below;

• to manufacture medicines and chemicals

• domestic purposes

• electricity

• water sports

Multiple Select

Water in dams generates electricity, this is also known as

• geothermal plant

• biomass

• hydroelectric power plant

• fossil fuel

Multiple Choice

What is the melting point of ice?

• 100 degree celsius

• 0 degree celsius

• 10 degree celsius

• none of the choices

Multiple Choice

What is the boiling point of water?

• 0 degree celsius

• 10 degree celsius

• 100 degree celsius

• 20 degree celsius

Multiple Choice

What is the process by which solid ice change to liquid water?

• freezing

• melting

• evaporation

• condensation

Multiple Choice

What process by which gas change into liquid?

• freezing

• melting

• condensation

• evaporation

Multiple Choice

A Process by which liquid water change to ice is known as ________

• freezing

• melting

• evaporation

• condensation

Distribution of Earth's Water

-2/3 part of our planet is covered with water, only a small amount is available for our use.

-About 97% of the water on the Earth is salty and only 3% is fresh water consist of 30% groundwater, 1 % surface water.

-All of this fresh water is not available for human use, as over 2/3 of fresh water is frozen and it is present in the form of ice at glaciers and polar ice caps.

WATER or Hydrological Cycle

is a repeat process of water present in Earth's surface evaporates due to heat of the sun. The evaporated water when reaches to atmosphere, the cooler air condenses it into droplets. The droplets collectively form clouds. When clouds become heavy and cannot hold more water, the water droplets fall on the Earth as rain called precipitation. After falling, it again evaporates.

Terms:

Precipitation - is water that falls to the earth as hail, mist, rain, sleet, or snow.

Condensation-is the process where water vapor becomes liquid.

SOURCES OF WATER

1. Rainwater- is the main source of water.

-The purest form of water, but while falling down to the Earth it gets polluted with dust and particles and some dissolved gases.

2.SURFACE WATER

- is the water that collects on the surface of the Earth

-includes; ocean, seas, lakes, rivers, and wetlands.

-Seas and oceans covers 70% of the Earth's surface.

-Salinity-is the condition of water being salty due to salts that dissolved in it.

-Desalination- to remove salt from sea

3.Groundwater or underground water is present below the Earth's surface.

• Rainwater penetrates through the ground and stores over the non-porous layers of rocky bed.

• Hydrogeology- is the study of the groundwater.

• Infiltration- the process of seeping(flow) of water under the ground

Aquifer-is the water reservoir formed above the impervious(water cannot flow) layers of rock.

• The area where water fills the aquifer is called saturated zone. The upper layer of this zone or aquifer is called water table.

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• Artesian well-is a water well that doesn't require a pump to bring water to the surface; this occurs when there is enough pressure in the aquifer.

QUIZ TIME

Multiple Choice

How many percentage of water on Earth is salty?

• 70%

• 50%

• 97%

• 10%

Multiple Choice

How many percentage on Earth's water is a fresh water?

• 10%

• 20%

• 3%

• 5%

Multiple Choice

It is a repeated process of evaporation and precipitation known as ______

• hydrological cylce

• condensation cycle

• sublimation cycle

• water-nitrogen cycle

Multiple Select

Precipitation ______

• a form of rain or snow

• is a liquid to gas

• solid to liquid

• the water droplets falling on the Earth

Multiple Select

Sources of water are as follows;

• surface water

• rainwater

• infiltration

• groundwater

Multiple Choice

What is considered as the purest source of water?

• groundwater

• surface water

• rainwater

• lakes

Multiple Choice

It is a process of removing salt in the sea is known as ____

• salinity

• aquifer

• infiltration

• desalination

Multiple Choice

What is the upper layer of aquifer?

• saturated zone

• water table

• artesian plane

• tube-well

Multiple Choice

As water seeks its own level, the water rises and forces itself out of the Earth's surface, this form is called ________

• aquifer

• saturated zone

• artesian well

• water table

Multiple Choice

What do you call the process of seeping of water under the ground?

• aquifer

• infiltration

• hydrogeology

• water tab;e

Multiple Choice

______ is the condition of water to become salty

• desalinity

• non-porous

• salinity

• saturated

Multiple Choice

What water source whichis 97 % of the Earth's surface?

• groundwater

• rainwater

• suface water

• water table

Multiple Choice

-________ it is the study of groundwater.

• Hydrological

• Hydrogeology

• Hydrothermal

• Hydroelectric