Class VI

Ch-1 The Planet Earth and the solar system                                                       

D: Answer the following questions in brief:-

Q-1 What are celestial bodies?

A-1 The sun the stars, the moon the planets and other objects are all heavenly or celestial bodies.

Q-2 What is ‘’ SAPRISHI MANDAL’’ ?

A-2  Ursa major also called the Great bear, is a constellation of several stars. In India , the seven stars called SAPTRISHI MANDAL , is a part of great bear.

Q-3 Why do stars look very small in the sky?

A-3 Stars are very huge bodies, they look very small as they are very far away from the earth.

Q-4 Name the planets which are gaseous bodies ?

A-4 The planets which are gaseous bodies are Jupiter, Saturn, Uranus and Neptune.

Q-5 Which planet is the closest to Neptune?

A-5 Uranus planet is the closest to Neptune.

E: Answer the following questions:-

Q-1.Derscribe the formation of solar system?

Ans 1

1 Some scientists believe that a giant cloud of gas and dust called the Nebula appeared moving in the space about 4.6 billions of years ago.

2. It cooled and gained very fast rotation.

3. The eight vale of gases of different sizes separated from the Nebula.

4. The remaining central mass of the Nebula changed into a star known as the sun

5. The other eight balls changed into planets.

Q-2 State three features which make the earth a unique planet.

A-2 The three features which make the earth a unique planet are-

   

    1)   The earth receives moderate heat and light from the sun. This much quantity of heat and light is just sufficient to evolve and sustain all forms of life on the Earth's surface. Other pets are either very hot or very cold.

    2)   About two-thirds of Earth's area is covered with water. Water is essential for human beings, animals and plants. No life can exist without water.

    3)   The earth has an envelope of air around it. It contain gases, water vapours and dust particles which help in supporting life on the planet. Earth's atmosphere protects is from the the incoming meteoroids.

Q-3 Mention three main characteristics of a satellite.

A-3 Three main characteristics of a satellite are-

1) The heavenly bodies that revolve around their respective planets are called satellite.

2) Satellite don't have their own light and heat. They reflect light which they receive from the sun.

3)Each planet has one or more satellites, except the Mercury and the Venus.

Q-4 Give a brief description on the phases of moon with the help of a diagram.

A-4 .1 The visible portion goes on increasing gradually day by day after the new moon day.

2. At first, the moon appears in Cresent shape.

3. On eight day, half portion of the moon comes in our view.

4. The full moon becomes visible are 15 days when half of its revolution is completed. The day when the moon is completely visible to us, is the Full Moon Day (Purnima)

5.After this day, the decline of the moons illuminated part starts. The illuminated part slowly disappears and the moon again cooled back to the position of new moon.

DIAGRAM ON PAGE NO. 8

Q-5 Write a short note on the other celestial bodies (asteroid, meteoroids and comets) in the solar system.

A-5

ASTEROIDS- Asteroids are Rocky, space objects that orbit our sun. These can be a few feet wide to several hundred miles wide. Most Asteroids orbit our sun, a star, on a region of space between the orbits of Mars and Jupiter known as the asteroid belt.

METEOROIDS- Meteoroids are little chunks of rock and debris in space. They become meteors is shooting stars when they fall through the Earth's atmosphere, leaving a bright trail as they are heated by the friction of the atmosphere. Most of them break up in the atmosphere before they can strike the surface as meteorites

COMETS- Comets are small bodies with a head and long luminous tail. They are made up of dust and frozen gases. They appear in the sky after a long period of time.