Water Class 6 Notes CBSE Science Chapter 14 [Free PDF Download]

• Water is the essential day to day need of an individual.

•  Most of the household activities depend on water like bathing, washing, cooking etc.

• It is also important because it is the basic demand of a human being to survive.

How Much Water Do We Use? 

• Water covers one-third of earth surface present in seas, oceans, in the form of glaciers etc.

• But still only $2\%$ freshwater is available for drinking and other uses.

• We use water in our day-to-day activities and for producing many new things.

• Water is also used in agriculture as well as the industrial sector.

Where Do We Get Water From?

• The $2\%$ water which is available for drinking and other use is present in rivers, lakes, ponds and wells.

• The water in seas and oceans is salty therefore unfit for our use.

• Water in rivers, lakes, ponds and wells comes from seas and oceans by the help of water cycle.

• We also get water glaciers as it melts into water. 

Water Cycle

• Continuous circulation of water on the earth is called the water cycle.

• The cycle involves evaporation of water from the surface of earth such as seas, oceans, rivers, lakes etc. to form water vapors

• The water from the plant is also lost in the form of vapors by the process of transpiration.

• As the water vapor is formed and moved upwards it condenses to tiny droplets by the process of condensation

• These tiny droplets come together to form clouds and by the process of precipitation the water comes back to earth in the form of rain 

• This rain water is fresh and fit for our use.

• The diagrammatic representation of water cycle is shown below

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• This is how the salty water from seas and oceans is converted into fresh drinking water.

Back To the Oceans

• The land surface is slightly elevated from the water surfaces such as seas and oceans.

• Therefore, water from the rain and glaciers all sweeps down into the seas and oceans.

• Rain water and snow melts also recharge ground water.

• Groundwater is water that is present below the earth's surface and is fresh for our use.

What if it Rains Heavily?

• The excess rainfall increases the water level in water bodies which leads to floods.

• Flood is the overflow of water which submerges land causing destruction.

• Floods cause loss of livelihoods by washing away people and animals.

• It also provides damage to infrastructures and disrupts the supplies of clean water causing a situation of water scarcity.

What Happens if it Does Not Rain for A Long Period?

• No rainfall can decrease the water level in water bodies and ground water level also decreases due to excess transpiration which leads to drought.

• Drought is the situation when there is no water available for even drinking, the complete dryness is drought.

• Drought leads to the shortage of water supplies eventually leads to loss of livelihoods.

How Can We Conserve Water?

• Out of surplus water present we have access to only a small fraction of water.

• With an increasing population, the demand for water consumption is also increasing.

•  The increased demand for water consumption and careless use of this natural resource leads to shortage of water.

• We must adopt some measures to conserve water.

• Sustainable use of water can help us to save water for the future also.

Rainwater Harvesting

• One major to conserve our source of freshwater is rainwater harvesting.

• Rainwater Harvesting is a technique of conserving rain.

• There are two types of rainwater harvesting techniques 

1. Roof-top harvesting technique: In this rainwater is collected on the roof of house then it flows down in the tank on ground or pit in the ground through the channel of pipes.

2. Direct flow of rainwater in ground

• Rainwater harvesting provides many benefits such as reducing demand on ground water, providing water for drinking purposes, reducing flood and soil erosion etc.