earth

Do you know which planet we live on?
We all live on a small blue planet called Earth. It has enough space for each of us, our families, friends, animals, birds and plants. Earth is the only place in the universe where life is known to exist.

From space, Earth looks like a blue ball with white swirls. The blue part of the Earth is because of water. Water covers most of the Earth. There is more water than land on Earth. About three-fourth part of Earth is covered with water and only one-fourth part is the land where we all live. Earth is also known as a blue planet.
Earth is surrounded by invisible gases that form a thin protective blanket that we call the atmosphere. It contains the oxygen that we breathe as well as other important gases such as nitrogen, carbon dioxide, water vapor, and ozone.

We get light from the sun that helps plants and animals to grow. The heat from the sun keeps the earth warm and hence it supports life on this planet. Because of air, sunlight, and water, life exists on Earth.

Earth's shape and movement

The Earth is spherical in shape. It is never stationary. It keeps moving. It shows two types of movement - rotation and revolution.

Rotation

Have you ever seen a top spinning? Top spins on a point in a vertical line that passes through its center. This fixed line is imaginary and is called the axis. Similarly, Earth also rotates around its axis from the west to the east. Earth's axis doesn't stand up straight, it is slightly tilted. The Earth takes 24 hours to complete one rotation. Now you understand why we have a day equal to 24 hrs? This means a complete rotation has both day and night

Equator

The Equator is an imaginary line around the center of the Earth, that divides the Earth into two equal halves: the Northern and Southern Hemispheres. 

The North Pole is at the northernmost point of the Earth, while the South Pole is at the southernmost point on the Earth. The area around the North and South Poles is very cold but the area around the equator is very warm.

Have you seen a globe?
It is a small model of our planet earth. It is a picture of Earth drawn on a sphere. The sphere of the globe represents the Earth. Like Earth, it rotates around a fixed axis that is slightly tilted. Globe helps us to see what Earth looks like. Have you noticed that the globe is mostly blue in color? That is the part of Earth covered with water. The remaining portion is the land divided into countries and continents. Try to locate your country in a globe.

How do day and night occur?

During the rotation of the Earth, one-half of the Earth faces the sun and the other half away from the sun. The half that faces the sun directly experience daytime and the other half experience nighttime. Day and night follow each other as the Earth rotates around its axis every 24 hours.

 

Revolution

Along with rotation, Earth also revolves on a fixed path around the sun. The fixed path on which the Earth goes around the sun is called the orbit. The position of the Earth in its orbit around the Sun determines the season of the Earth. The time taken by the Earth to revolve around the Sun once is 365¼ days, that is the time that defines a year for us.
The revolution of Earth around the Sun and the Earth's tilt causes a change in seasons.

Both rotation and revolution of the Earth happen at the same time.

 

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Some more facts

• Earth is about 4.54 billion years old.
• The moon revolves around the Earth as Earth revolves around the sun.
• Like Earth other planets also revolve around the sun. The collection of eight planets and their moons in orbit around the Sun is known as the solar system.
• Earth isn't exactly a sphere because it gets flat at the top and bottom and bulges in the middle.
• Earth Day is celebrated on 22nd April every year. On this day all over the world adults and children learn about how to keep our planet clean and green.