CBSE · Class 8 · Science · Chapter 11

Keeping Time with the Skies

Discover how observations of the Sun, Moon, stars and celestial cycles have helped people measure time.

7 lessons 40 min
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Lessons in this chapter

  1. 1Observing the Moon’s PhasesFollow the changing Moon and learn when and where its different phases are easiest to observe.
  2. 2Explaining Moon Phases and MoonriseUse sunlight and changing viewpoints to explain Moon phases, their timing, and their connection with tides.
  3. 3Natural Cycles and Units of TimeDiscover how repeating events in the sky give us days, months, and years.
  4. 4Lunar, Solar, and Luni-solar CalendarsLearn how calendars reconcile unequal natural cycles with whole days and recurring seasons.
  5. 5Indian Calendars and FestivalsConnect Indian month systems, the National Calendar, and festival dates with their astronomical reference cycles.
  6. 6Artificial Satellites and Their UsesExplore human-made objects in orbit, their everyday uses, and the challenge of space debris.
  7. 7Summary & PracticeConnect the complete chapter through visual reasoning, calendar calculations, and mixed practice.
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