Time Keeping

Time Keeping

Published: 2002

The Islamic Calendar
The Islamic Calendar (or Hijri calendar) is purely lunar. It has 12 months based on the moon’s motion, and because 12 synodic months total only 12 x 29.53 = 354.36 days, the Islamic calendar is consistently shorter than a tropical year. As a result, it shifts relative to the Christian calendar. Based on the Qur’an (Sura IX, 36-37), Muslims consider its proper observance a sacred duty. The Islamic calendar is the official calendar in Gulf countries, especially Saudi Arabia. Other Muslim countries use the Gregorian calendar for civil purposes and turn to the Islamic calendar only for religious purposes.

Islamic Timekeeping Water Clock
What is Taught:
Until the 14th century, the only type of clock available was the water clock. In 1335, Milan, Italy, saw the erection of a large mechanical clock. This was possibly the first weight-driven clock.

What Should be Taught:
Spanish Muslim engineers produced a variety of mechanical clocks, both large and small, and transmitted this knowledge to Europe through Latin translations of Islamic books on mechanics. These clocks were weight-driven.

They provided designs and illustrations of epicyclic and segmental gears. One such clock included a mercury escapement. Europeans directly copied this type in the 15th century. Besides, during the 9th century, Ibn Firnas of Islamic Spain, according to Will Durant, invented a watch-like device that kept accurate time. The Muslims also constructed a variety of highly accurate astronomical clocks for use in their observatories.

What is Taught:
In the 17th century, Galileo developed the pendulum as a teenager. He noticed a chandelier swaying in the wind. As a result, he went home and invented the pendulum.

What Should be Taught:
Ibn Yunus al-Masri discovered the pendulum during the 10th century and was the first to study and document its oscillatory motion.
Muslim physicists recognized its value for clocks in the 15th century.