Waterbodies PDF

## Waterbodies **Key Concepts** * Waterbodies * Lake, river and waterfall * Ocean and sea **Look at the pictures which show the different uses of water. Can you think of some more uses of water?** ### Waterbodies Do you know which part of our Earth is covered with land and which part is...

## Waterbodies **Key Concepts** * Waterbodies * Lake, river and waterfall * Ocean and sea **Look at the pictures which show the different uses of water. Can you think of some more uses of water?** ### Waterbodies Do you know which part of our Earth is covered with land and which part is covered with water? * Nearly three-fourths of the Earth's surface is covered with water. That is why, the Earth is also called the 'Blue Planet'. * A waterbody is a collection of water anywhere on the surface of the Earth. There are different kinds of waterbodies on Earth. These waterbodies are of different sizes. Any waterbody will have either fresh water or saline water. Fresh water is the purest form of natural water that does not contain any salts, for example, rainwater. <br/> | Land | Water | | --- | --- | | | | | *Ratio of land and water on Earth* | | <br/> (Salty water is known as saline water. It is not suitable for human beings, plants and animals. In the previous chapter, we have learnt that the surface of the Earth has different types of landforms. Now, let us explore the different types of waterbodies found on the surface of the Earth) ### Lake * Alot of people go for picnics to a lakeside. * A lake is a large body of still water surrounded by land on all sides. Lakes are formed when water collects in large, deep areas on the Earth's surface. Lakes may contain fresh water or salty water. * You must have seen small waterbodies in villages and outside the cities. These are called ponds. A lake is bigger and deeper than a pond. The largest freshwater lake in the world is Lake Superior in the United States of America. **Lake Superior** ### River * A river is a large natural course of running water which empties into another large waterbody. Rivers usually have fresh water and flow from a higher place to a lower place. The starting point of a river is in the mountains, and it is called the source of the river. The point where the river empties into a larger waterbody, like the sea, a lake or an ocean, is called the mouth of the river. * As the river flows from the source to its mouth, it collects rainwater and water from other small streams, springs, etc., on its way. A stream is a small body of flowing water. A spring is a natural source of water which comes out to the surface of the Earth from under the ground. **River flowing into the sea** **Main river** **Mouth of the river** **Tributary** <br/> * A tributary is a freshwater stream that joins a larger stream or river. A river can have many tributaries. The Ganga is the most important river in India. It has many tributaries. The most important tributary of the Ganga is the Yamuna. The other important rivers of the world are the Mississippi in North America, the Amazon in South America, the Nile in Africa and the Hwang-Ho in Asia. **97 per cent of the water on the Earth is found in oceans and seas. But, we cannot use this water as it is saline or salty.** ### Waterfall * What happens when a river flows from a height, over an edge of hard rocks? A spectacular sight is created. This fall of a river or any other body of water over a rocky edge is called a waterfall. Some of the most popular tourist spots across the world are near waterfalls. Some of the most famous waterfalls are the Niagara Falls, the Victoria Falls and the Angel Falls. **Angel Falls** **Create your own river and waterfall.** * Take a glassful of water in a tray. Take a bucket of water and tilt the tray slightly to pour the water in the bucket. Observe how the water flows from a high area to a low one and how a waterfall is formed. ### Sea * A large body of salty water on the surface of the Earth is called a sea. Some seas are part of the oceans and partially enclosed by land. The land along the edge of the sea is called a sea beach. Sea beaches are famous for their natural beauty-the golden sand, sea shells and huge waves. It might sound strange, but there are many mountains and deep valleys under the seas and oceans as well! **Make an octopus from a sock.** * Cut a sock from the heel. Stuff it with cotton and tie it with a rubber band. Then, slit the portion below the rubber band into 8 strips to make the tentacles. Paste buttons to make the eyes. Your octopus is ready to swim in the ocean! <br/> (Have you ever wondered why seawater is salty? As the rivers flow along different kinds of rocks, they carry many minerals and salts along with them, down to the seas and oceans. These minerals and salts keep getting collected in the seas and oceans, making them salty. So, the salt that we use in our food is made from the salty water of the seas and oceans. The names of some important seas are Arabian Sea, Mediterranean Sea and Caspian Sea. * There is a sea by the name of Dead Sea. It has been given this name because it is the saltiest sea and there is no plant or animal life in or around it! **An Arabian Sea coast in Goa** ### Ocean * Oceans are the largest and the deepest waterbodies on Earth. They have salty water. You already know that there are five oceans in the world-Pacific Ocean, Atlantic Ocean, Arctic Ocean, Indian Ocean and Southern Ocean (Antarctic Ocean). **Arctic Ocean** **Atlantic Ocean** **Pacific Ocean** **Indian Ocean** **Southern Ocean** * **Map not to scale** * **Major oceans of the world** <br/> (The Pacific Ocean is the largest and deepest ocean. The only ocean in the world which is named after a country is the Indian Ocean). It lies to the South of India. Thousands of aquatic creatures such as different types of fish, octopus, whales, prawns, crabs, etc., live in oceans. There are also many types of plants and seaweed that grow inside the ocean. **Now, look at different waterbodies in and around India.** **Why is the ocean water not suitable for drinking?** <br/> **Map of waterbodies in India:** A map of India showing the following: * **Rivers**: Yamuna, Ganga, Gandak, Mahanadi, Son, Narmada, Tapi, Godavari, Krishna, Tungabhadra, Kaveri, * **Lakes**: Sambhar Salt Lake, Nizam Sagar, Nagarjuna Sagar, Kolleru Lake, Pulicat Lake, Vembanad Lake, Chilika Lake. * **Seas**: Arabian Sea, Bay of Bengal * **Islands**: Lakshadweep (India), Andaman and Nicobar Islands (India) * **Map Key**: Rivers, Lakes, Ocean * **Map not to scale** * **Waterbodies of India** **aquatic creatures**: animals who live in water