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 In the last decades, these clocks have almost disappeared, having been replaced by watches with atomic or electronic oscillations, which are much more accurate and reliable than the previous ones.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 Minute is a unit used to measure time intervals and corresponds to 60 seconds. A very common error of students happens when they intend to convert from one unit of time to another. If we have for example 5.25 minutes, many will interpret this information as equivalent to 5 minutes and 25 seconds. This conversion is wrong! Notice that 0.25 is a quarter, so a quarter of a minute is 15 seconds. Thus, the correct conversion of 5.25 minutes is 5 minutes and 15 seconds. Generally, a minute is the time it takes for the blood to take a full turn in our body. As a matter of curiosity, be aware that, currently approximately 65,000 barrels of oil per minute are spent, which corresponds to the volume of four Olympic pools.