๐ Class 8 Science – Curiosity Chapter 11
๐ Keeping Time with the Skies
๐ข 1. State whether the following statements are True or False.
(i) We can only see that part of the Moon which reflects sunlight towards us.
✅ Answer:
True
(ii) The shadow of Earth blocks sunlight from reaching the Moon causing phases.
❌ Answer:
False
(iii) Calendars are based on various astronomical cycles which repeat in a predictable manner.
✅ Answer:
True
- Earth’s rotation → Day
- Moon’s revolution → Month
- Earth’s revolution → Year
(iv) The Moon can only be seen at night.
❌ Answer:
False
๐ข 2. Amol was born on 6th of May on a full Moon day. Does his birthday fall on the full Moon day every year? Explain your answer.
❌ Answer:
No, it will not fall on a full Moon day every year.
๐ง Explanation:
- The Gregorian calendar is based on Earth’s revolution (365 days).
- The lunar cycle (full Moon to full Moon) is about 29.5 days.
๐ Conclusion:
3. Name two things that are incorrect in Fig. 11.10.
Answer:
(ii) List the picture labels of the phases of the Moon that are never seen from Earth.
See Answer From Earth, we never see (B) new moon phase.
๐ข Question 5, 6 and 7 of Class 8 Science Curiosity Chapter 11
๐ข 5. Malini saw the Moon overhead in the sky at sunset.
(i) Draw the phase of the Moon that Malini saw.
✅ Answer:
๐ Half Moon (First Quarter Phase) ๐
(ii) Is the Moon in the waxing or the waning phase?
✅ Answer:
๐ Waxing Phase ✔️
๐ง Explanation:
- Waxing = illuminated part increasing ๐
- First Quarter Moon appears:
- ๐ rises around noon
- ๐ overhead at sunset
๐ข 6. Ravi said, “I saw a crescent Moon, and it was rising in the East, when the Sun was setting.” Kaushalya said, “Once I saw the gibbous Moon during the afternoon in the East.” Who out of the two is telling the truth?
✅ Answer:
๐ Kaushalya is correct ✔️
๐ง Explanation:
๐ Waxing Gibbous Moon:
- Rises in afternoon ๐ค️
- Seen in eastern sky ✔️
๐ Crescent Moon:
- Seen near setting Sun (west side) ๐
- ❌ Cannot rise in east at sunset
๐ข 7. Scientific studies show that the Moon is getting farther away from the Earth and slower in its revolution. Will luni-solar calendars need an intercalary month more often or less often?
✅ Answer:
๐ Less often ✔️
๐ง Explanation:
๐ Difference ≈ 11 days
๐ If Moon slows down:
- Lunar month becomes longer ⏳
- Lunar year becomes longer
๐ Difference reduces
๐ข Class 8 Science Curiosity Chapter 11 Question 8 and 9
๐ข 8. A total of 37 full Moons happen during 3 years in a solar calendar. Show that at least two of the 37 full moons must happen during the same month of the solar calendar.
✅ Answer:
๐
3 years = 36 months
๐ Full Moons = 37
๐ง Logic:
๐ข 9. On a particular night, Vaishali saw the Moon in the sky from sunset to sunrise. What phase of the Moon would she have noticed?
✅ Answer:
๐ Full Moon ๐
๐ง Explanation:
๐ Full Moon:
- Rises at sunset ๐
- Visible all night ๐
- Sets at sunrise ๐
๐ข Class 8 Science Curiosity Chapter 11 Question 10, 11 and 12
๐ข 10. If we stopped having leap years, in approximately how many years would the Indian Independence day happen in winter?
✅ Answer:
๐ Approximately 500 years ✔️
๐ง Explanation:
๐
Calendar error = 0.25 days/year
๐ข 11. What is the purpose of launching artificial satellites?
✅ Answer:
๐ฐ️ Uses of Artificial Satellites:
- ๐ก Communication (TV, mobile signals)
- ๐งญ Navigation (GPS)
- ๐ฆ️ Weather forecasting
- ๐จ Disaster management
- ๐ฌ Scientific research
- ๐บ️ Mapping & planning
๐ข 12. On which periodic phenomenon are the following measures of time based:
✅ Answer:
