PATTERNS IN TIME
CHALAKIM
Every halachic hour is divided into 1080 chalakim or parts. A part is 3⅓ seconds or minute. Some say that 1080 is used since that number was evenly divisible by all numbers from 1 to 10 except 7. (Chalakim are commonly heard when the chazan announces the new moon at the time of blessing the new month on the previous Shabbos called “M’varchim HaChodesh”).
Math fact: 1080 is the smallest number with 18 divisors
Based on the above, please answer the following:
- How many chalakim in one minute?
- How many chalakim in 20 minutes?
- How many chalakim in 35 minutes?
- How many minutes in 180 chalakim?
- How many minutes in 540 chalakim?
- How many minutes in 1350 chalakim?
One lunar cycle is 29 ½ days and 793 chalakim תשעה ועשרים ומחצה ותשצ"ג חלקים -
Thus, each lunar cycle exceeds a set of 4 weeks (28 days) by a set period known as אי"ב תשצ"ג (א – one day י"ב 12 hours תשצ"ג 793 chalakim)
Therefore, if the “molad” (beginning of lunar cycle) of one month is known, one can calculate the time of the “molad of the next month.
Therefore, if Molad Nissan is on the first day of the week in the fifth hour of the day and 107 chalakim, add the “remainder” of אי"ב תשצ"ג , and the molad of Iyar is the night of third day of the week, in the 5th hour of the night, and 900 chalakim (example from Rambam Hilchos Kidush haChodesh 6:7).
- To first day add one day = second day of the week
- To the fifth hour add 12 hours = the 5th hour of the following night (becomes third day of week)
- To the 107 chalakim, add 793 = 900 chalakim
- Calculate the Molad of Sivan from the above example:
- Calculate the Molad of Tamuz from the above example:
- Calculate the Molad of Av from the above example:
OBJECTIVE:
FAMILIARITY WITH THE PATTERNS OF TIME IN JEWISH LAW
AGE GUIDE:
NINE YEARS OLD AND OLDER (THROUGH ADULT)
Why didn’t Chaza”l break the minute into 60 parts just as they calculated the hour?
Rabbi Yosef Sonnenfeld answers that this was done so that when calculating a lunar cycle we have no fractions of a second as a lunar cycle is completed in 29 days, 12 hours, and 793/1080th of an hour. Alluded to in the verse in Tehillim (104,19) “Oseh yo’reiach l’mo’adim” (“He has created the moon for set times”), whose numerical value is 793.
