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Water Resources and Conservation - The Water Cycle and Rainfall

Grade 5CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

The Water Cycle, also known as the Hydrological Cycle, is the continuous movement of H2OH_2O between the Earth's surface and the atmosphere.

Evaporation: The process where liquid H2OH_2O is heated by the Sun and turns into water vapor (gas).

Transpiration: A biological process where plants release excess H2OH_2O into the atmosphere through tiny pores in their leaves called stomata.

Condensation: The process where water vapor cools down high in the atmosphere and turns back into tiny liquid droplets to form clouds (VaporightarrowLiquidVapor ightarrow Liquid).

Precipitation: When the water droplets in clouds become too heavy, they fall back to Earth as rain, snow, sleet, or hail.

Infiltration and Collection: Rainwater flows into rivers, lakes, and oceans (collection) or soaks into the soil to recharge groundwater (infiltration).

Rainwater Harvesting: A conservation technique where rainwater is collected from rooftops and stored for future use or used to recharge groundwater levels.

📐Formulae

ightarrow H_2O ( ext{vapor})$$
ightarrow H_2O ( ext{liquid/clouds})$$

extTotalPrecipitation=extRunoff+extInfiltration+extEvapotranspiration ext{Total Precipitation} = ext{Runoff} + ext{Infiltration} + ext{Evapotranspiration}

💡Examples

Problem 1:

During a hot summer day, a puddle of H2OH_2O on the road disappears after a few hours. Name the process involved and explain why it happens faster when the temperature TT is high.

Solution:

The process is Evaporation.

Explanation:

Evaporation is the change of H2OH_2O from liquid to gas. As the temperature TT increases, the molecules of water gain more kinetic energy, allowing them to escape into the air as vapor more rapidly.

Problem 2:

A student notices droplets forming on the outer surface of a glass filled with ice-cold water. Is this part of the water cycle? Explain.

Solution:

Yes, this demonstrates Condensation.

Explanation:

The water vapor present in the surrounding air comes into contact with the cold surface of the glass. The loss of heat energy causes the H2OH_2O vapor to turn back into liquid droplets, mimicking how clouds form in the atmosphere.

Problem 3:

If a locality receives 1200extmm1200 ext{ mm} of rainfall annually but faces water scarcity in summer, what conservation method should be adopted?

Solution:

Rainwater Harvesting.

Explanation:

Rainwater harvesting allows the collection of H2OH_2O during the rainy season to be stored in tanks or used to replenish the underground water table, ensuring availability during dry months.