3 ms·

12 notes, 12 hours, 12 months., even 12 monkeys.

• lioeters 4y ago
  > The duodecimal system, which is the use of 12 as a division factor for many ancient and medieval weights and measures, including hours, probably originates from Mesopotamia. https://en.wikipedia.org/wiki/Duodecimal#Advocacy_and_%22dozenalism%22 https://en.wikipedia.org/wiki/Duodecimal#Advocacy_and_%22doz...
  • retrac 4y ago
    Yep. 60 seconds, 60 minutes, 12 hours. To the Sumerian mind that was apparently as nice and round as 100 seconds, 100 minutes, 20 hours. 60 is the smallest composite number with three prime factors, and divides evenly by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30. Decimal only divides by 2 and 5. Makes arithmetic by hand a lot easier. Duodecimal has a similar advantage.
    • mandmandam 4y ago
      > 60 is the smallest composite number with three prime factors Er, that'd be 30 I think, but the main point stands.
      • BitwiseFool 4y ago
        2 is such a nifty prime, we multiplied by it twice. It was just too perfect not to.
• marginalia_nu 4y ago
  The numbers 12 (2x2x3), 24 (2x2x2x3), 30 (2x3x5), 60 (2x2x3x5) and 360 (2x2x2x3x3x5) crop up in a lot of older counting systems because they're so conveniently divisible.
  • abudabi123 4y ago
    One twelfth the atomic weight of one carbon-12 atom is the atomic mass constant. What does string theory sound like? https://periodic.lanl.gov/79.shtml https://periodic.lanl.gov/79.shtml http://en.wikipedia.org/wiki/Atomic_weight http://en.wikipedia.org/wiki/Atomic_weight
    • marginalia_nu 4y ago
      The atomic mass constant is arbitrarily defined as 1/12th the weight of a C-12 atom, it has historically also been defined as 1/16 the weight of an oxygen atom but changed to C-12 because it behaves better.