EN हिं

NCERT Solutions for Curiosity Chapter 11 Keeping Time with the Skies

Updated on 2026-09-05

About this chapter

The Moon does not shine by itself. Sunlight always lights exactly one half of it. The half turned towards the Earth is not always the lit half, so on different days we see different fractions of the lit half — these are the phases of the Moon . In the waning period (Krishna Paksha) the bright part shrinks from a full circle to nothing in about two weeks; in the waxing period (Shukla Paksha) it grows back. One full Moon to the next takes about 29.5 days . Phase and position go together. On full Moon day the Moon is opposite the Sun (it rises at sunset); on new Moon day it is in almost the same direction as the Sun. Because the Moon moves about 12° eastward each day, it rises about 50 minutes later every day. Three natural periodic events give three units of time — Earth's rotation gives the

  • Chapter opener
  • .1 How Does the Moon’s Appearance Change and Why?
  • .1.2 Locating the Moon
  • .1.3 Making sense of our observations
  • .2 How Did Calendars Come into Existence?
  • .3 Are Festivals Related to Astronomical Phenomena?
  • .4 Why Do We Launch Artificial Satellites in Space?
  • End-of-chapter questions
  • Science • Society • Interdisciplinary Projects
Read the chapter

Exercises

  1. Chapter opener — Probe and ponder Page 170
  2. .1 How Does the Moon’s Appearance Change and Why? — Activity 11.1: Let us explore Page 17211
  3. .1.2 Locating the Moon — In-text Questions Page 17311
  4. .1.2 Locating the Moon — A step further Page 17311
  5. .1.3 Making sense of our observations — In-text Questions Page 17411
  6. .1.3 Making sense of our observations — Activity 11.2: Let us explore Page 17411
  7. .1.3 Making sense of our observations — In-text Questions Page 17611
  8. .2 How Did Calendars Come into Existence? — In-text Questions Page 17811
  9. .2 How Did Calendars Come into Existence? — Activity 11.3: Let us measure a day! Page 17811
  10. .3 Are Festivals Related to Astronomical Phenomena? — In-text Questions Page 18311
  11. .4 Why Do We Launch Artificial Satellites in Space? — In-text Questions Page 18511
  12. End-of-chapter questions — Keep the curiosity alive Page 187
  13. Science • Society • Interdisciplinary Projects — Discover, design, and debate Page 188
Was this helpful? Report an error

More Class 8th solutions

English Hindi Maths Sanskrit Social Science