The scientific heritage of the ancient Egyptians is known from techniques more than theoretical science. Writings describe results from the application of mathematics, astronomy, medicine, and geometry. The ancient Egyptian people knew decimal numbers and fractions and were able to calculate areas, such as the areas of circles, rectangles, and triangles.
Astronomy was very important to the Egyptians, who observed the sky regularly and created the Egyptian calendar. Ancient Egyptians were concerned with the annual cycle of the seasons to establish the time for cultivating and harvesting. For astronomers and priests, however, time was extremely important. They were responsible for determining the exact hour for daily rituals and important religious festivals. Sundials, which were invented by the Egyptians, allowed the astronomers and priests to observe the passing of the 12 daylight hours. Amenemhat created the first water clock, the Clepsydra, which enabled the ancient Egyptians to measure the passing of every 12 hours, both night and day, winter and summer. This water clock had 12 carved columns of 11 false holes, corresponding to the hours of the night. The water flowed through a very small hole made in the center of the bottom, emerging on the outside. To know the time, one had to look inside the basin to observe the water level and read the time according to the nearest false hole.
During the Greco-Roman era, the intellectual leadership shifted from Athens to Alexandria. Egypt was home to a growing scientific and cultural movement for more than seven centuries. The ancient Library of Alexandria and its associated Museum gave birth to a new intellectual dynamic. By gathering together all the known sources of knowledge and organizing them for the purposes of scholarly study, the Ptolemaic rulers marked the foundation of the modern idea of the research institute and university. Within this haven of learning, the arts and sciences flourished. The Library included about 700,000 books in different fields of knowledge. Scholars and scientists visited it to deposit copies of their works. The Ptolemies ensured that all the famous scientists in this period were financed for their research, with no condition or restriction. They also offered many privileges to the scientists to encourage them to stay in Alexandria.
The battles and controversies of the famous authors and scholars of that period led to the establishment of scientific schools in Alexandria in the fields of literature, philosophy, geometry, mathematics, astronomy, physics, and geography. Knowing these sciences was a must for every cultured person. This scientific atmosphere resulted in the emergence of a large number of Egyptian scientists in different fields. The most famous scientist was the geographer, Ptolemy, in the second century AD, who combined his knowledge of geography, mathematics, and astronomy to make the first world map with the right dimensions. Plotinus, a believer in Gnosticism, combined the philosophy of Plato and others to come up with his own philosophy about the world of the abstract mind.
In the Islamic Era, especially since the third century AH, a wide translation movement started, through which the Arab culture collected scientific information from the previous cultures. By drawing on a variety of texts and translating them into Arabic, the early scholars accumulated the greatest body of scientific knowledge in the world and built on it through their own discoveries. Arabic scholars formed new intellectual schools. The Arabic language became the language of knowledge and learning for many centuries. It was only later, in the twelfth and thirteenth centuries, when the Arabic works began to be translated into Latin that such knowledge passed to the west.
Systematic scientific thinking, which depends on descriptive observation, was the most important contribution of the Arabic sciences. Often, scientific thinking was exercised for a practical and religious purpose. Astronomy could be used to determine the direction of prayer. Mathematics was needed for dividing property according to the Islamic law of inheritance. The sciences of language, logic, mathematics, gravity, chemistry, physics, and medicine flourished. A scientist who was versed in many sciences could be a philosopher, mathematician, astronomer, physicist, doctor, and chemist, sometimes also a historian, geographer, and poet. The most famous Arab scientists were Jabir Ibn Haiyan, Muhammad Bin Musa al-Khwarizmi, Yaqub Ibn Ishaq al-Kindi, Abul Wafa Muhammad al-Buzjani, and Abu Ali al-Hussain Ibn Abdallah Ibn Sina.