Measurement of Time

Introduction

Measurement of time is an important topic in physics. It lays the strong base for multiple numerical and other calculations. The other important concepts include the smallest measurement of time. 

Measurement of time

Time is the idea that revolves around our daily lives. It can be simply defined as the dimension on which the evolution of time takes place. It is easy to measure time in different small and big units. Further, the measurement of time is expressed with past, present, and future indications.

The past is defined as the presence of an event before the given point of time reference. The present is defined as the presence of an event at that given point of time reference. The future is defined as the presence of an event at an indefinite time reference.

The measurement of time is used to keep time, follow time, and tell the time in multiple applications. These can be scientific or regular applications. When it comes to motion and forces in physics, time is ideal for calculations.

Einstein’s theory of relativity improved the measurement of time. It has helped in introducing the concept of slowing time with gravity and motion. It is the measure of events that starts from the past to the future. It is further measured with the duration of events and intervals between these events. While there are three spatial dimensions, length, breadth, and height, time is the fourth dimension. Hence, the measurement of time is helpful for understanding and applying the time in different applications.

Smallest measurement of time:

Before jumping to the units, it is essential to know the SI unit of time, i.e., second. It is denoted by “s”. 60 seconds constitute one minute, and one hour constitutes 3600 seconds. Further, there are 86,400 seconds in one day.

Coming to time measurements, it is not an easy procedure. In the earlier times, when there were no instruments to measure time, people used to take the reference of the periodic changes like change of seasons, sunrise, sunset, etc. The periodic motion was set to repeat at a specific interval that defined the time at that time. Hence, the time taken by any object to repeat its movement is period, and the number of repetitions was termed frequency. The unit used for measuring the frequency of the event is Hertz.

Hence, before the invention of instruments, sunrise and sunset were the only means of measuring time for different persons. The other popular periodic movements in the measurement of time were the movement of stars in the sky, water flow, changing of the seasons, the phases of the moon, etc.

Quick measurements:

• Measurement of month: The moon takes around 29.5 days to change its phase from full moon to the next phase
• Measurement of the year: The change of seasons was used to measure the years. It was used to find the rainfall time in previous years that marked the right time for cultivation

Instruments used to measure time:

Sundials:

The crude sundials were formed using a rod that is stuck upright in the ground. The shadow of the rod changes with the movement of the sun in the sky and hence forms the sundial. Needless to say, it was not helpful to keep time during the night.

Hourglasses:

The hourglass consisted of two glass bulbs. The top glass consisted of sand, and a defined amount of the sand was sent down to the bottom bulb at a specific time. Its close association is that of the water clock that is used in different parts and works on the principle of regulating water flow. The clock using the flow of water from one container to another to measure time is termed a water clock. However, the time calculations of the water clock varied due to the flow of water.

Pendulum:

The least accuracy of the sundials and hourglasses was best managed by the invention of the pendulum in 1656. The first pendulum clock was made by Christiaan Hygens which was made up of weights and a swinging pendulum. The pendulum clock solved all possible issues of the sundials and hourglasses and is more reliable than the previous measurement of time.

Quartz clock: 

The invention of the atomic clock further helped solve portability and quick time-keeping. It was the quartz clock that was created in the 1930s by Albert Einstein that proposed the theory of relativities that defined time as the fourth dimension.

Conclusion:

In this article, we explained the measurement of time. The SI unit of time is seconds or “s”. The clock is the primary instrument used to measure time. In earlier times, sundials and hourglasses were used to measure time.