How Did Ancient Egyptians Invent the 24-Hour Day?

The 24 on your phone screen is Egyptian. The 60 next to it is not - and the people who invented the 24 never once saw an hour that stayed the same length. Egypt did not divide time. Egypt divided daylight: sunrise to sunset cut into twelve, however long that happened to be, so a summer hour was physically longer than a winter one and everybody lived inside the stretch. This video follows that idea through four surviving objects - a workmen's limestone sundial from the Valley of the Kings, star tables painted facing inward on the underside of coffin lids, the alabaster water clock from Karnak with twelve separate scales cut inside it so it could keep up with the changing hour, and a stone decree from 238 BC. That decree is the strangest part. The Egyptian calendar ran 365 days flat with no leap day, so it slid backwards through the seasons by about a day every four years. They knew. In 238 BC the Canopus Decree proposed the fix - one extra day every fourth year, the same fix your calendar uses now - and it was abandoned in the face of resistance from the priesthood. It took until roughly 22 BC for a leap year to hold. Rome applied the patch Egypt refused: Caesar's astronomer Sosigenes of Alexandria built the Julian calendar on the Egyptian 365-day year, and that framework is the Gregorian calendar today. What did not survive is the stretching hour. Your hour is the same in June and December, not because anyone proved the Egyptians wrong, but because a clock with gears cannot easily be told to make July's hours longer. You inherited the Egyptian count with the Egyptian meaning taken out of it. Where the evidence runs out, this video says so: nobody has found a document explaining why twelve, and the workmen's sundial measuring shifts is the excavators' most likely reading, not a proven fact. Sources: The Metropolitan Museum of Art, "Telling Time in Ancient Egypt" Susanne Bickel, University of Basel, Valley of the Kings sundial, reported in Live Science and Archaeology Magazine, 2013 Clepsydra of Karnak, reign of Amenhotep III, Egyptian Museum Cairo JE 37525 Encyclopaedia Britannica, "Clepsydra" Encyclopaedia Britannica, "Egyptian calendar" Canopus Decree, 238 BC, under Ptolemy III Sothic cycle, on the drift of the 365-day civil year Encyclopaedia Britannica, "Sosigenes of Alexandria" and "Julian calendar" Scientific American, "Why is a minute divided into 60 seconds, an hour into 60 minutes, yet there are only 24 hours in a day?" Encyclopaedia Britannica, "12-hour clock" ABC Science, "Why are there 24 hours in a day?" If you want more of the ordinary working life the documentaries skip, subscribe. #AncientEgypt #HistoryOfTime #EgyptianHistory