Our Earth

Unit 1

OUR EARTH

Imayan is waiting for his father in the evening, after returning from school. His father is an employee in a reputed bank

Imayan: Come Daddy! (Imayan ran and hugged his father)

Father: what Imaya? Had your snacks?

Imayan: Yes, I had!

Father: What are you doing? Have you completed your homework?

Imayan: My social teacher told to draw solar system will you please help me?

Father: Yes Sure.

Imayan: She is going to teach about Earth tomorrow. She told to gather information about earth. Please tell me about that dad.

Father: Oh! Ok. I will tell you.

Imayan: How did the earth originate?

Father: Millions of years ago an explosion called the big bang occurred.Numerous stars and celestial bodies came into existence by that massive explosion. These celestial bodies together called the Universe. It is also referred to as cosmos.

Imayan: Will you explain about Universe, Daddy?

Father: The Universe is a vast expanse of space. The Universe consists of billions of galaxies, stars, planets, comets, asteriods, meteoroids and natural satellites. The exact size of the universe is still unknown. Scientists believe that the universe is still expanding outward.

Imayan: What is the galaxy, daddy?

Father: Galaxy has a huge cluster of stars. Our galaxy ‘Milky way’ is one of the countless billions of galaxies in the Universe.

Imayan: Ok Daddy. What is Solar system?

Father: Solar system consists of the sun, the planets, their moons, dwarf planets, asteroids and comets. These objects are gravitationally bound.

Imayan: Very interesting dad. Tell me about our solar system.

Father: There are 8 planets in our solar system. The outer planets are Gaseous planets. They are Jupiter, Saturn, Uranus and Neptune. The inner -rocky planets are Mercury, Venus, Earth, and Mars. They are called Terrestrial planets. The frozen planets are Uranus and Neptune.

Activity

Make the Globe.

Imayan: Then, where is our Earth daddy?

Father: The Earth is the third planet from the sun and the fifth largest in the solar system

Imayan: It is said that the earth is rotating itself and at the same time revolving around the sun. Is it true?

Father: Yes, it has two movements. They are rotations and revolution. The earth rotates on its axis. It is called rotation of the earth. It also revolves around the Sun. It is called revolution of the earth. Day and night are caused due to the earth’s rotation. Seasons are caused by Earth’s revolution. Life is possible only on earth because of the presence of land, air and water.

Imayan: Oh! I see. What is the distance between the sun and the earth?

Father: The distance is nearly 150 million kilometre between the sun and the earth.

Imayan: Say some interesting facts about Planets dad?

Father: Mercury and Venus lie near the sun. Next to Earth is Mars, Jupitar, Saturn, Uranus and Neptune. The planets nearer to the sun are very hot. The planets away from the sun are very cold. Mercury is the smallest planet. Venus is called Earth’s twin. Mars is described as the Red planet. Earth is called the Blue planet. Saturn is the Ringed planet.

Imayan: Wow! Amazing! Where do we live on the Earth?

Father: We live on the surface of the Earth. It is made up of 7 continents and 5 oceans.

Imayan: 7 continents!! What are they?

Father: Listen. They are: Asia, Africa, North America, South America, Antarctica, Europe, and Australia.

Imayan: Which is the biggest continent?

Father: The Asian continent where we live is the biggest of all. And Australia is the smallest one. The Antartica is the continent full of snow.

Imayan: What are the five oceans Daddy?

Father: Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean and Southern Ocean. Do you know that around 97 percent of the planet’s water is in the Ocean?

Imayan: Is it so, Daddy?

Father: Yes, Around 71 percent of our Earth is covered by salt water and that is called as Ocean. Only 2.5 percent of water is fresh and 1 percent of it is easily accessible.

Imayan: Thank you, Daddy. Today I have learnt a lot about the earth from you. Now I am going to study and do my home work.

Father: Ok, Imaya. Go and study.

Do you know?

Birla Planetarium is located in Chennai which provides virtual tour of the night sky and planets of the solar system.