When they invented the clock, how did they know what time it was?
Rafael Fernandes Junqueira,
Mirassol D’Oeste, MT
In fact, our ancestors knew the time of day long before the clock was invented. The mechanical clock is an invention of the 14th century, while the division of the day into 24 hours appeared around 5000 BC in Babylon. The key point of this numerical system was the definition of noon. Observing the movement of the shadow caused by the Sun, the Babylonians discovered that there was a moment when the star was upright in the sky, without projecting shadows to the sides. This moment became known as noon. The Babylonians then divided the rest of the shadow’s path into 12 parts: six before noon (morning) and six after (afternoon). The division of the day into 24 parts (hours) was created – the other half, of course, was the night. To mark the trajectory of the shadow, the Babylonians created the sundial.
historical punctuality
Humanity has already used stars and melted wax to count the minutes
Instrument – Sundial
Where it was used – Babylon
When – 5000 BC
Humanity’s first clock had a rod that projected the sun’s shadow in a marking divided into 12 parts. The “12” was chosen because it is a sub-multiple of 60, which was the basis of the Babylonian mathematical system.
Instrument – Mechanical watch
Where it was used – Europe
When – 14th century
Despite having appeared in the 14th century, the mechanical clock only became popular in the 18th century. The first models were driven by gears connected to small weights, which were not very accurate.
Instrument – Candle clock
Where it was used – Europe
When – 9th century
The first record is from the 9th century, but this “clock” was so simple that many historians believe it was invented centuries earlier. It was a graduated candle that, as it burned, showed how many hours had passed.
Instrument – Clepsydra
Where it was used – Egypt
When – 3500 BC
The first “night” clock that we have proof of is the clepsydra. To tell the time at night, the Egyptians created a mechanism in which a water container emptied at a controlled flow, moving an hour dial.
Instrument – Astrolabe
Where it was used – Greece
When – 2nd century BC
The astrolabe was a Greek invention that ended up being lost in history, only being “reinvented” in the 14th century. Same
solar time
Want to build a sundial? See how easy it is
1. Place in the center of a flat surface — bathed in sunlight all day — a rod about 20 cm long. To improve visibility, tilt the rod a little, in the direction of the projected shadow.
2. Follow the movement of the shadow, which will decrease towards the stem until noon. When the shadow starts to grow again, make a mark on the surface at that position. this is noon
3. On the surface, make a semicircle centered on the rod and its noon marking. Divide this semicircle into 12 parts, six before the center point (morning) and six after (afternoon).