Water clocks, also known as clepsydras, are ancient timekeeping devices that measured time by regulating the flow of water into or out of a container. The first water clocks consisted of a ceramic vessel with a hole at the base to allow a steady flow of water, indicating the passage of time. Later versions featured multiple containers to distinguish between day and night periods. Water clocks date back to ancient Egypt, Greece, Rome, and China, with innovations over centuries improving their design and accuracy.

1. The Water Clock or
Clepsydra

2. What are they?
 The waterclocks or clepsydras
are a type of mechanism for
measuring time by the regulated
flow of liquid to or from a
graduated container, thus two
different types of clocks
according to the direction of
flow.

3. How were they?
 The first water clocks consisted
of a ceramic vessel containing
water to a certain level, with a
hole at the base of an adequate
size to ensure the liquid outlet at
a given speed and, therefore, in
a predetermined time.

4. How did they work?
 The container available within
several brands so that the water
level indicating the different
periods, day and night.

5. Backgrounds
 In the year 1530 B.C. a vessel was built for King
Amenhotep I in Egypt with water clock features.
 In the Temple of Amun at Karnak found a water clock
dating from the fourteenth century BC
 In the fourth century B.C. Plato invented an alarm
clock that used a water clock.
 In ancient Greece and Rome was measured by the
time to talk about water clocks.
 In the third century B.C. Ctesibius, a student of
Archimedes, developed a water clock with numerical
indicators.
 His Chinese Sung Cio described and built a water
clock with mechanical elements in 1090.
 In 1982 he developed a water clock 13 m high located
in Berlin.
Information from: Wikipedia