SHORT ANSWER TYPE QUESTIONS
Q. 1. What are celestial bodies?
Ans. The stars, the planets, the moon and many other objects in the sky are called celestial bodies.
Q. 2. Define phases of the moon.
Ans. The various shapes of the bright part of the moon as seen during a month are called phases of the moon.
Q. 3. Why do we see only the part of the moon?
Ans. We see only that part of the moon from which the light of the sun is reflected towards us. So we see only the part of the moon.
Q. 4. Why does the size of the moon decrease every day after the full moon day?
Ans. After the full moon day the sunlit part of the moon visible from the earth decreases in size every day.
Q. 5. Why do we classify the sun as a star?
Ans. The sun is a star because it has its own source of energy and continuously emits heat and light.
Q. 6. Why are stars invisible during the day time?
Ans. Stars are far away from us compared to the sun. So the glare of the sun is much more than the glare of star during the daytime. Therefore stars are not visible during the day time.
Q. 7. What are planets?
Ans. The celestial bodies which revolve around the sun are called planets. There are eight planets in the solar system.
Q. 8. Why do stars twinkle but planets not?
Ans. The stars are very far away from the earth. The point position of the stars vibrate to disturbance by air currents and hence they appear to twinkle. The planets are much nearer than of stars and they do not have disturbance by air current, so they do not twinkle.
Q. 9. Define orbit.
Ans. A planet has a definite path in which it revolves around the sun. This path is called orbit.
Q . 10. What are Asteroids?
Ans. There is a large gap between the orbit of Mars and Jupiter. This gap is occupied by a large number of small objects that revolve around the sun. These are called asteroids.
Q . 11. What is meteor?
Ans. At night, when the sky is clear and moon is not there, sometimes bright streaks of light may be seen in the sky. This is called meteor.
Q . 12. What are meteorites?
Ans. Some meteors are so large that they do not completely evaporate before reaching the earth. These are called meteorites.
Q . 13. What is artificial satellite?
Ans. A man made satellite which is orbiting the earth is called artificial satellite.
Q . 14. What are comets?
Ans. Comets are the members of our solar system. They revolve around the sun in highly elliptical orbit as a bright head with a long tail.