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This one in the picture is not only the oldest water clock and technological device for measuring time in the history of civilizations left to us from the ancient world, but its recent re-examination and study provided the explanation and the reason why the Egyptian clock became the master of time measurement for more than three thousand years in the world, as it turned out to be Evidence of the Egyptians’ knowledge of the principles of physics, specifically: fluid dynamics (the science that specializes in studying the flow and flow of liquids and gases).
The Egyptians invented two types of water clocks: outward-flowing clocks (including this one, which is the oldest) and inward-flowing clocks, in addition to their invention of the first sundials.

This clock made of alabaster in the picture, which dates back to the era of the great Egyptian king (Amenhotep III) around 1400 BC, and whose cases were found in Karnak in the Egyptian city of Thebes (currently Luxor), has been proven to have concealed in its design a physical law that has not been found. In Europe, except in the seventeenth century by the Italian physicist Evangelista Torricelli, this Egyptian clock, 3,500 years ago, was the first embodiment of this physical law that

Describes and controls the flow of fluids from a hole in a vessel. When the Egyptians invented this scientific masterpiece to measure time at night in the absence of the sun, they measured time using vertical columns inside which had graduated points, and a hole at the bottom from which water flowed. However, choosing any shape for the clock vessel would have been included. Measuring time is chaotic, so that the measurement becomes distorted after the height of the liquid in the container decreases. As a result of the difference in the pressure of the liquid as it continues to flow from the hole in the container, the speed of the flow will change and therefore the amount of liquid flowing from the hole will change, as it is fast at the beginning and slows down when the height of the liquid decreases.But the Egyptian inventor, after experimenting and testing, arrived at what is known today as Torricelli’s Law, which says that the relationship between the flow speed, the acceleration, and the height of the liquid in the vessel is a direct relationship. In other words: the Egyptians arrived at the conclusion that by using a certain geometric shape (which is the shape of the ellipse cone of the clock The flow speed and the amount of liquid emerging from the watch vessel are equal to the decreasing pressure as the liquid continues to decrease, which practically fulfills the principles of the law formulated by (Torricelli), three thousand years after the Egyptians achieved it in clock engineering, and this is the secret of the survival of its technology and Its effectiveness was adopted by the Bonanists, Romans and Arabs, until it was replaced by the mechanical clock in the Middle Ages, and this is also the reason that made scholars of Egyptian civilization and the science of measuring time in it more advanced and great and had the upper hand and superiority over all other civilizations, as Anna Schomberg says. ) Ancient technology expert.

In the comments, examples of the Egyptian clock were found in Greece, 1000 years after its invention. Egypt, as well as an Arabic manuscript from the Islamic era about the manufacture of the water clock thousands of years after its invention in Egypt.
Sources: 1- The Karnak water clock and its successors: Egypt’s contribution to the invention of time measurement, Anna C. Schomberg, 2019.
2- Ancient Egyptian Science, Volume Two: Calendars, Clocks, and Astronomy, Clagett Marshall.