3rd Grade ICSE

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09. Water As A Resource

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Last edited 37 days ago by Learn LoopHQ.

Chapter: 09. Water As A Resource

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Explain the key properties of water and why it is considered a vital resource for life on Earth.

Water is an extremely important resource as life cannot exist without it. It is primarily a liquid at common temperatures, making it easy to transport and use. Water also exists in solid (ice) and gaseous (water vapour) forms, allowing it to move through different phases in nature. Furthermore, water is known as a universal solvent because it can dissolve a wide variety of substances, which is crucial for biological processes and nutrient transport. Its unique properties enable countless daily activities like drinking, cleaning, and cooking, underlining its indispensable role for all living organisms.

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Describe the processes of evaporation and condensation, providing a real-world example for each.

Evaporation is the process where liquid water changes into water vapour, which is a gaseous form, due to heating. The rate of this transformation significantly increases when the liquid is boiled. A common example is when water in a pot on a stove heats up, it turns into steam and disappears into the air. Condensation is the reverse process, where water vapour (gas) cools down and transforms back into liquid water droplets. An everyday example is seeing water droplets form on the outside of a chilled bottle or glass; this happens because the warm water vapour in the air cools upon contact with the cold surface, turning into liquid water.

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Illustrate the continuous journey of water through the water cycle, explaining its main stages.

The water cycle is the continuous journey water takes as it moves between the land and the sky, and then back to the land. It begins with evaporation, where the Sun’s warmth heats water in lakes, rivers, and oceans, turning it into water vapour that rises into the air. As this water vapour ascends, it cools down and undergoes condensation, forming tiny water droplets that combine to create clouds. When these clouds become saturated and heavy with water, the water droplets fall back to Earth as precipitation, which can be rain or snow. Finally, this water is collected in various bodies like rivers, lakes, oceans, or as groundwater, restarting the cycle as it eventually evaporates again.

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Differentiate between the three types of impurities found in water, providing examples for each.

Water from natural sources often contains various impurities, making it unsafe for direct consumption. The first type is insoluble impurities, which are substances that do not dissolve in water and can be easily seen. Examples include sand, mud, tiny stones, and twigs. The second type is soluble impurities, which are substances that dissolve completely in water and therefore cannot be easily seen. Salt dissolved in water or the dissolved components in soft drinks are common examples. The third and most dangerous type is germs, which are extremely tiny, harmful living organisms that are invisible to the naked eye but can cause severe waterborne diseases.

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Detail various methods by which water can be purified, particularly focusing on methods applicable at home.

To make water safe for drinking, impurities and germs must be removed. At home, several methods can be used for purification. Boiling is considered the easiest and most effective method, as heating water to its boiling point for at least 10 minutes effectively kills most harmful germs. Filtering is another common method, where water is passed through a filter (like a cloth or a specialized water filter) to physically remove insoluble impurities such as dirt and particles. Additionally, chlorination involves adding chlorine tablets to water; these tablets release chlorine which kills germs that cause waterborne diseases like cholera and jaundice, making the water safe to drink. In larger scales, water is purified at facilities called waterworks before being supplied to homes.

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Explain the concept of rainwater harvesting and its significance for future water availability.

Rainwater harvesting is an essential method of water conservation, involving the collection and storage of rainwater for future use. This practice aims to prevent rainwater from running off and being wasted by gathering it from hard surfaces like rooftops or the ground. The collected water can then be stored in dedicated tanks or through the construction of check dams. Its significance is immense, as it provides a valuable alternative water source, especially crucial during periods of water scarcity or drought. By implementing rainwater harvesting, communities can secure a more sustainable water supply, reduce reliance on groundwater, and contribute to overall water security for the future.

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