Student Orientation with Robert James

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The Concept of Time and Its Measurement Throughout History

Early Civilizations and Their Timekeeping Methods

Introduction

Humans have been intrigued by time for thousands of years. Since the earliest days of civilization, humans have developed many time keeping systems to better comprehend their world. The need to measure and track time has driven the development of sundials, water clocks, and hourglasses. Each system was a result of human creativity and the cultural environment in which it existed.

Sundials

A sundial is one of the first recorded time-keeping tools. They date back to approximately 1500 B.C.E. in ancient Egypt and Mesopotamia. The primary function of a sundial is to measure time based upon the shadow of the gnomon (the vertical rod) cast upon the horizontal dial. The sun’s movement creates the shadows, causing the shadow to move across the dial. Thus, measuring time occurs as the shadow travels. The simple design and efficiency of sundials enabled them to be used in many different civilizations throughout history. While sundials were useful for tracking time during the daylight hours, they were limited by being unable to accurately keep track of time during overcast conditions. For hundreds of years, sundials remained a key component in advancing the art of time keeping.

Clepsydra (Water Clocks)

Clepsydra, or water clocks, became a viable alternative to sundials for measuring time. Clepsydra were able to be used during both daytime and nighttime hours. Water clocks are believed to have evolved around 4000 B.C.E. in ancient China and continued to evolve through Egypt and Mesopotamia. A typical clepsydra includes two containers; a top container filled with water and a bottom container where the water drips out through a small opening. The amount of water that collects in the bottom container is directly related to how much time has passed.

In addition to using clepsydra as a basic form of timekeeping, the Greeks and Romans improved this method by incorporating mechanical components. For example, they incorporated gear mechanisms into the design and placed dials to increase the accuracy of the clepsydra. Ctesibus of Alexandria, a Greek philosopher, designed a sophisticated water clock in 3rd Century B.C.E., which featured a dial and pointer to illustrate the time. Although water clocks did offer some advantages over sundials, they too had several disadvantages. Factors such as changes in temperature and contaminants within the clepsydra may cause variations in water flow rates, requiring periodic maintenance. Regardless of these limitations, water clocks provided a major improvement over earlier forms of timekeeping and were extensively employed by numerous ancient civilizations.

Hourglasses (Sand Glasses)

Hourglasses are believed to have originated in Europe in the Middle Ages, but there is no definitive information regarding when exactly they began to be used. Unlike sundials and water clocks, which depend on natural phenomena to determine time, hourglasses utilize sand as a means to measure elapsed time. An hourglass contains two cylindrical glass containers attached together at a very narrow neck. Once inverted, sand flows slowly from the upper glass container into the lower glass container due to gravity at a consistent rate. Therefore, once calibrated properly, hourglasses allow users to measure time as well as determine the length of time it will take for the sand to completely empty from the upper container into the lower container. Hourglasses were frequently employed for a variety of purposes including navigation, cooking, and timing religious ceremonies. Portability and simplicity allowed hourglasses to become an acceptable instrument for measuring time in multiple environments across different cultures and historical eras. Like other early forms of timekeeping, hourglasses require proper calibration and observation in order to provide reasonably accurate measurements.

Conclusion

Early civilizations’ attempts to develop precise methods of measuring time resulted in three distinct types of innovations – sundials, clepsydras/water clocks, and hourglasses. Each type of innovation reflected the distinct cultural and technical backgrounds of their respective creators. Together these ancient methods of measuring time greatly increased humanity’s understanding of what constitutes time itself. Ultimately, the pioneering work of sundials, clepsydras/water clocks and hourglasses established foundational principles for the subsequent designs of advanced clocks and watches. Furthermore, these early timekeepers demonstrate our society’s ongoing attempt to conquer time itself as we continually develop new technologies.

Quick Quiz

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