The Earth- Oceans, and Continents Class 3 Notes SST

Earth

Earth is the planet we live on! It's like a giant ball floating in space, and it's where all life as we know it exists. It's got land, water, air, and lots of different environments, like forests, deserts, oceans, and mountains. 

Our Planet Earth

How the Earth was Formed?

• Formation of the Solar System: About 4.5 billion years ago, our solar system formed from a swirling cloud of gas and dust.
• Formation of Earth: Within this cloud, tiny particles collided and stuck together, forming Earth over time.
• Differentiation: Earth's core formed as heavier materials sank, while lighter materials rose to the surface.
• Cooling Down: Earth gradually cooled, forming oceans and an atmosphere from volcanic activity.
• Evolution of Atmosphere: Early atmosphere mainly had carbon dioxide and water vapor, later changing due to the evolution of living things.

So, Earth formed through the accumulation of matter, cooling, and the evolution of its atmosphere, becoming the planet we know today!

Our Wonderful Earth!

The most wonderful thing about our beautiful earth is that its distance from the Sun is just perfect that it is not a hot ball or extra cold.

• The distance from the Sun allows life to exist over here. It also allows the atmosphere to build and helps life to grow. 
• The earth too has a family member. It is the moon. The moon is the satellite of the earth.
• When the earth was formed, a part of the earth separated from it and formed the moon. The moon moves around the earth as the earth moves around the Sun. 
• That way the earth and the moon both move around the Sun.

Moon is the satellite of Earth

• It is very hot deep inside the earth. We live and work on the outermost surface of it.
• We could find out about the formation of the inner part of the earth whenever it bursts open and the hot material is thrown out of it.
• It is a terrifying experience which no one likes to happen.

What is the Shape of Earth?

The Earth is almost completely round.

• Whether the earth was flat like a disc or a plate or like a ball had been a point of discussion for a pretty long time. It was not that earlier people were not wise as we are but they had to depend mostly on observation or guesswork. 
• For them, stars were twinkling dots, and with naked eye, moon was more like a disc than a ball. They had intelligence but no means to find the truth. 
• Some people did believe that heavenly bodies were sphere-like. Based on that belief, in the 16th century, Ferdinand Magellan of Portugal undertook a daring journey by sea and after three years reached the same place where he started the journey three years before.
  

• It was more daring than the journey of the first astronaut from the earth to the moon. Now we are definite about the shape of the earth. Such incidences tell us about the courage of man in search of truth and knowledge.

The Oceans on Earth

Oceans are large bodies of saltwater. These are really very large. Earth has five major oceans, which are large bodies of saltwater that cover most of the planet's surface. Here they are:

• Pacific Ocean: The largest and deepest ocean, stretching from the Arctic in the north to the Antarctic in the south. It's known for its vastness and the Ring of Fire, an area with many earthquakes and volcanoes.
• Atlantic Ocean: The second-largest ocean, separating the Americas from Europe and Africa. It's known for its strong ocean currents, including the Gulf Stream.
• Indian Ocean: The third-largest ocean, located between Africa, Asia, Australia, and the Indian subcontinent. It's known for its warm waters and the monsoon winds.
• Southern (or Antarctic) Ocean: Surrounding Antarctica, this ocean is the youngest and smallest of the five. It's known for its cold temperatures and strong westerly winds.
• Arctic Ocean: The smallest and shallowest ocean, located around the North Pole. It's covered with sea ice, and its size can vary with the seasons.

These oceans play a crucial role in regulating the Earth's climate, providing habitat for diverse marine life, and influencing weather patterns around the globe.

Fun Facts about Oceans

• The smaller bodies of saltwater are called the sea. All the oceans and seas are interconnected. So the level of water in the sea and the oceans remains the same.
  
  Oceans and Continents of the World
• This level is taken as the standard for measuring every other level whether of water or the land. At whatever level the aeroplane flies is measured from the sea level. 

• The height of Mount Everest is also measured from sea level. Taken together, the water in oceans and seas is more than two-thirds of the earth’s surface. 
• Oceans look like plain water surfaces but under such water surfaces, there are deep valleys and high mountains.
• Oceans are full of lives. Besides fishes, there are many marine lives yet to be discovered. 
• Arctic and Antarctic oceans have large chunks of ice as large as hills floating in them. They are called Iceberg.

Ice berg

The Continents on Earth

Continents are large unbroken landmasses. The Earth's surface is divided into seven main pieces of land called continents. Here they are:

Continents

• Asia: It's the largest continent, home to countries like China, India, Russia, and Japan.
• Africa: The second-largest continent, known for its diverse wildlife, deserts, and ancient civilizations.
• North America: It includes countries like the United States, Canada, and Mexico, and is known for its vast forests, mountains, and urban areas.
• South America: Known for the Amazon rainforest, the Andes Mountains, and countries like Brazil, Argentina, and Peru.
• Antarctica: It's the coldest and driest continent, covered in ice and home to penguins, seals, and scientific research stations.
• Europe: Known for its rich history, diverse cultures, and countries like France, Germany, Italy, and the United Kingdom.
• Australia: Sometimes called a continent and a country, known for its unique wildlife, including kangaroos and koalas, as well as its vast Outback.

Europe and Asia form one big mass. These two together are named Eurasia. Our country India is a part of Asia.

Globe and Maps

• A model of the Earth, is called a globe, shows us the whole Earth. We can rotate it to see different places. However, a globe is not big enough to show all the places in detail. 
• To solve this problem, we have drawing of a part of the Earth, or the whole of it. Such drawings are called maps. A map can be big or small. A book of small maps is called an atlas.