The Second was historically calculated as a function of the Earth's rotation. However, it was understood that the earth's rotation was too imprecise and therefore it was decided to measure the second according to the Earth's revolution around the Sun. Over the last three hundred years, the pendulum was the most reliable time. For a pendulum clock to be able to accurately measure time, the range of motion must be kept constant. This is not easy, since frictional losses have an influence on the mechanical system of the watch. Small variations in the amplitude of the pendulum's movement, such as 4° or 5°, make the clock ahead about 15 seconds per day. To compensate for this variation, pendulum clocks use a weights system, which is intended to provide additional energy to the pendulum, and thus compensate for frictional losses. In the last decades, these clocks have almost disappeared, having been replaced by watches with atomic or electronic oscillations, which are much more accurate and reliable than the previous ones.
The Hour is a unit used to measure time intervals and corresponds to 60 minutes or 3600 seconds. In historical terms, this measure was calculated based on the rotation of the planet Earth. As of 1928, virtually every country in the world has adopted universal time. To determine the time in a given location, simply add or subtract an integer number of hours to universal time. This addition or subtraction will depend on whether we are located east or west of the Greenwich meridian. Between two consecutive time zones there is always a difference of one hour. As a curiosity, know that for every hour that passes are consumed more than 12 million cans of Coca-Cola and more than 1 million hamburgers.