Keeping Time with the Skies | Class 8 Science Notes

Calendars

This section discusses the development and importance of calendars in human society. Calendars are systems to organize days, weeks, months, and years for social, religious, and economic activities. The section explains how ancient civilizations used lunar calendars based on the Moon's phases and solar calendars based on the Sun's apparent motion. The lunar calendar has months of about 29.5 days, making a lunar year about 354 days, shorter than the solar year. To reconcile this difference, some calendars add extra months occasionally. The Gregorian calendar, widely used today, is a solar calendar with 365 days and a leap year every four years to adjust for the extra 0.25 days. The section emphasizes the need for accurate calendars for agriculture, festivals, and administration. It also mentions the Indian calendar systems and their basis on astronomical observations.

📊 Diagram: Table comparing lunar and solar calendars, showing months, days per month, and total days per year.

🧪 Activity: No specific activity in this section.

🔗 Connection: Leads to the section on clocks and how time is measured precisely.