# Class 7 Science Chapter 16 Water A Precious Resource Notes

Last updated on August 30th, 2023 at 12:57 am

## Class 7 Science Chapter 16 Water A Precious Resource Notes

Q: When is World Water Day?

World Water Day is celebrated on 22nd March.

Q: What is the recommended amount of water by the United Nations for daily use?

The recommended amount of water by the United Nations for drinking, washing, cooking, and maintaining proper hygiene is a minimum of 50 litres per person per day.

Q: What is the estimated number of people who could face water scarcity in a few years?

It is estimated that in a few years from now, more than one-third of the people in the world could face water scarcity.

Q: What percentage of the earth’s surface is covered with water?

About 71% of the earth’s surface is covered with water.

Q: What are the different sources of water on earth?

The different sources of water on earth include seas and oceans, rivers, lakes, ice caps, groundwater, and the atmosphere.

Q: What is freshwater and where is it found?

Freshwater is the water that is fit for human consumption directly. It is found in rivers, lakes, underground aquifers, and glaciers.

Q: How does the water cycle maintain the total amount of water on earth?

The water cycle involves the continuous cycling of water among its three forms, which keeps the total amount of water on earth constant even when the whole world is using it.

Q: What is the water supply system in most towns and cities maintained by civic bodies?

The water supply system in most towns and cities is maintained by civic bodies. The water is drawn from nearby lakes, rivers, ponds or wells and is supplied through a network of pipes.

Q: How do people in many villages fetch water?

In many villages, people fetch water directly from sources like wells, tube wells, or hand pumps. Often, they have to walk several kilometres to fetch water.

Q: What is the water table?

The water table is the upper level of the layer below the ground where all the spaces between particles of soil and gaps between rocks are filled with water.

Q: Where does groundwater come from?

Groundwater comes from the water that seeps into the ground from precipitation like rain and snow. It can also come from nearby lakes, rivers, and other water bodies that recharge the groundwater.

Q: What is the process of seeping of water into the ground called?

The process of seeping of water into the ground is called infiltration.

Q: What is an aquifer?

An aquifer is a layer of hard rock below the water table where groundwater is stored.

Q: How is water in the aquifers usually pumped out?

Water in the aquifers is usually pumped out with the help of tube wells or handpumps.

Q: Can we keep on drawing water from under the ground? How will it affect the water table?

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