Water: A precious resources CBSE Notes class 7th Science

Water: A Precious Resource

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Water

➱Water is one of the most vital resources for all living organisms on Earth. Despite being abundant, only a small fraction is accessible and suitable for human use. This makes it essential to understand its availability, conservation, and sustainable usage for the future.

1. Availability of Water for Our Use

➥ Water is one of the most essential resources for life, but it is available in limited quantities. Only a small percentage of the water on Earth is fresh and accessible for human use.

1. Approximately 71% of the Earth's surface is covered by water.
2. Out of the total water on Earth, only 3% is fresh water, and less than 1% of this is easily accessible for human consumption.
3. The remaining fresh water is trapped in glaciers, ice caps, and underground reserves.

2. Forms of Water

➥ Water exists in three forms: solid (ice), liquid (water), and gas (vapor).

1. Solid: Ice in glaciers and ice caps.
2. Liquid: Rivers, lakes, and oceans.
3. Gas: Water vapor in the atmosphere.

Note:-

Water Cycle (Hydrological Cycle): - The water cycle, also called the hydrological cycle, is the natural process where water moves continuously between the Earth’s surface, atmosphere, and back again. This cycle plays a crucial role in maintaining life and balancing water on Earth.

3. Sources of Water

➥ >Water is obtained from various natural sources:

1. Rainwater: Precipitation that falls from the clouds to the ground.
2. Rivers and Lakes: Surface water sources that are often used for drinking and irrigation.
3. Groundwater: Water stored underground in aquifers, accessed by wells.
4. Desalination: The process of removing salt from seawater to make it drinkable.

4. Reasons for Depletion of Water Table

➥ The depletion of the water table is a serious environmental issue caused by various factors:

1. Increasing Population: The demand for water increases as the population grows.
2. Increasing Industrial and Agricultural Activities: Overuse of water for irrigation and industrial processes leads to depletion.
3. Climate Change: Changing weather patterns can reduce rainfall, contributing to water shortages.

5. Distribution of Water

➥ Water is not evenly distributed across the Earth. Some regions receive more rainfall, while others are arid and depend on groundwater.

1. Equatorial Regions: These areas experience abundant rainfall and have large rivers.
2. Arid Regions: These areas have limited water sources and often rely on underground water.
3. Mountainous Areas: Snowmelt from mountains feeds rivers and lakes.

6. Conservation of Water

➥ Water conservation is crucial to ensure its availability for future generations. Several measures can help conserve water:

1. Rainwater Harvesting: Collecting and storing rainwater for later use.
2. Efficient Irrigation: Using methods like drip irrigation to minimize water wastage in agriculture.
3. Recycling Water: Reusing water for non-potable purposes like industrial cooling.

7. Improving Water Economy

➥ Improving water economy means using water wisely to make sure we have enough for the future. Here are some simple ways to do it:

1. Water Pricing: Charge for water to encourage careful use.
2. Recycling Water: Reuse water for plants or factories instead of wasting it.
3. Rainwater Harvesting: Collect rainwater to reduce dependence on wells or rivers.
4. Smart Irrigation: Use methods like drip irrigation to water plants efficiently.
5. Better Water Systems: Fix leaks and improve storage to prevent water wastage.
6. Awareness: Teach people to save water, like turning off taps when not in use.
7. New Technology: Use technology to clean, reuse, or turn salty water into fresh water.

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