Until recently I didn't know who to remember my mother, and not for the better, when every morning a thunderous sound kidnapped me from the dream world of Morpheus and brought me back to harsh reality. Now I know, from the mother ofPlato , the inventor of the alarm clock.
The water clocks or clepsydras (from the Latin clepsydra and this from the Greek κλέπτειν , "steal" and ὕδωρ, "water") and sundials were the most common methods of measuring time in ancient times. The mechanism of the hourglass was very simple:a vessel was filled with water and allowed to flow out through a small hole located near the base of the vessel, creating a constant and regular flow that lowered the water level indicating the different periods marked on it. the inside of the vessel (it could also be done by filling the vessel with water on which the different periods are marked). But when waking up, the hourglasses were useless. Only roosters could be trusted, and those raised near the Academy of Athens, the philosophical school founded by Plato in 388 BC, were not to be trusted. So, the philosopher decided to adapt a clepsydra to turn it into the first alarm clock so that his students would not be late for his talks. Plato added to the hourglass a second vessel located on a lower level, hermetically sealed and connected by a tube. Inside the first he placed a siphon that, when the time was right, would make the water come out with enough force that when filling the second, the displaced air would escape through a small hole located in the upper part and would produce the sound, similar to that produced by the water vapor in the kettles.
Other later versions also used the clepsydras for this diabolical invention of humanity. It consisted of a container with water that poured its content into another in which a semicircular saucer with metal balls was placed and fixed with a hinge on its surface (similar to the method of the buoys of the cisterns that close the entrance of the water). When the water reached the saucer, it tilted it until the balls fell into a third metal container, causing a noise that would surely wake you up.
Source:The inventions of the ancients
