Ancient timekeeping device: Gnomon

The timekeeping devices used by different cultures are remarkably similar. The early inventions of the ancient civilizations of Egypt, Mesopotamian and Greece were crude and merely measured the amount of daylight versus nighttime hours.

The first of these devices is the gnomon, an early sundial. Sundials are considered to be the oldest form of timekeeping, although not in the form in the modern-day design.

The gnomon is essential a large stick place in direct sunlight. The time of day is determined by following the position of the shadow cast by the gnomon.

When the sun roses in the east, the pole will cast a long shadow to the west as the sun is shining directly onto the eastern-facing side of the pole.

As the sun rises in the sky, the shadow will slowly move to the northeast, finally pointing north at noon when the sun is at its highest in the sky, then gradually moving to the southeast as the sun sets, before ending in exactly the opposite position from its position at sunrise as the sun sinks beneath horizon.

The Babylonians and Egyptians divided the day into 12 units, six for sunrise to noon and six from noon to sunset.

Gnomons are used in Egypt in timekeeping for thousands of years. According to hieroglyphics texts, the measurement of time was central to the daily life of ancient Egyptians as early as the Old and the Middle Empires.

Greek astronomers of the Hellenistic period (around 550 BC) used the gnomon, a pole placed in the ground in an open field or area.
Ancient timekeeping device: Gnomon 

Around 3500 BC: ancient Egyptian develop timekeeping device

Understand the time of day and the seasons was crucial for prehistoric man’s ability to comprehend on for survivals. Once agriculture was invented, the time to plant and harvest could only be predicted by following the changing rhythms of the universe from season to season.

The ancient Egyptians recorded their dates according to the regnal year of the reigning king. So when a new king entered the throne, they started counting ten years again from one.

The ancient Egyptians were the first to introduce the concept of twenty-four hours in a day. Night and day were both divided into twelve hours. Prior to 127 BC, the length of the hours varied depending on the season. Early time keeping devices and calendars depended on the movement of the Sun and Moon.

Around 3500 BC, one of the first timekeeping devices, the gnomon is developed in ancient Egypt.
A gnomon is composed of a vertical stick that casts a shadow on the ground or a stone base when left in the sunlight. Scholars estimate the time by looking at the position of the shadow.

The gnomon is a precursor to the sundial. A sundial is a device for measuring the hour of a day. In general, a sundial consists of the gnomon that is also called the style and the surface engraved with the timescale for indicating the time of a day.

The shadow of the gnomon is projected on the surface. When the sun moves in the sky, the corresponding gnomon’s shadow moves in the surface. According to the position of the gnomon’s shadow, the hour of a day is identified.

And by 1500 BC, in Egypt, the sticks were replaced with monumental decorated spires called obelisks, which were built in city centers.
Around 3500 BC: ancient Egyptian develop timekeeping device