Page 158 - Innovator's Science-8

11. What is the purpose of launching ar ficial satellites?
Ans. Ar ficial satellites are launched for:
• Communica on • Naviga on
• Weather monitoring • Scien fic research

• Disaster management • Earth observa on
13. On which periodic phenomenon are the following measures of me based:
i. day ii. month iii. year?
Ans. i. Day → Earth’s rota on
ii. Month → Moon’s revolu on (phases of the Moon)
iii. Year → Earth’s revolu on around the Sun.

Put on your

Thinking cap Problem Solving Skills
A. Darken the correct options in the OMR Sheet: OMR Sheet

1. What do they call the Moon when it’s more than half lit but not full?
a. Crescent b. Gibbous
c. Quarter d. Eclipse Moon
2. What causes the phases of the Moon? Wrong Methods

a. The Earth’s rotation b. The Moon’s rotation Correct Method
c. The Moon’s orbit around the Earth d. The Sun’s movement
3. How long does one complete cycle of Moon phases take? 1. a b c d
a. 7 days b. 15 days

c. 29.5 days d. 365 days 2. a b c d
4. What is the phase when the entire face of the Moon is visible from Earth?
3. a b c d
a. First Quarter b. New Moon
c. Full Moon d. Waning Crescen
4. a b c d
B. Fill in the blanks.
Observational Skills
1. The _____________ of the Moon does not remain the same.
2. The changing shapes of the Moon that we see from Earth are called ___________.

3. The Moons rising time changes by about ______________ minutes every day.
4. The phase when the Moon is not visible from Earth is called ___________.
5. ______________ satellites appear as tiny moving dots in the night sky.

C. State whether the given statements are True (T) or False (F). Problem Solving Skills

1. We can only see that part of the Moon which reflects sunlight towards us.
2. The shadow of Earth blocks sunlight from reaching the Moon, causing phases.
3. Calendars are based on various astronomical cycles which repeat predictably.
4. The Moon can only be seen at night.

5. Countries send artificial satellites into space for different uses.
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