From a unit of time, usually the hour, we can organize any type of daily activity. When this happens we speak of periodization. It is a general concept that is projected onto all dimensions of existence, including geological ages and historical epochs.
We have the need to periodically organize what we do.
A traditional periodization consists of dividing the 24 hours of the day into three parts: eight hours for work, eight for sleep and the other eight dedicated to leisure and some obligations . The first way to measure time was the sundial, a system that began to be used 5000 years ago.
Since then, humanity has been incorporating new tools: the clepsydra (water clock), the hourglass (sand clock), the mechanical ( wrist ) clock and the atomic clock. Each of these technological advances allowed the timing of activities to be more precise and exact.
In a company that works 24 hours a day, the periodization is specified in three work shifts: morning, afternoon and night.
As a general criterion, each periodization aims to rationalize an activity. This implies knowing when something starts and ends, what are the established times and what needs to be accomplished. In a way, it can be said that there is no human activity that does not adopt a criterion of this nature.
Universal history and geological time
In addition to minutes, hours and days, we use a periodization of universal history in order to classify it and understand it better. The classic is as follows: Prehistory, Ancient Age, Middle Age, Modern Age and Contemporary Age. Each of them is successively divided into specific subperiods, which are measured in decades, centuries and millennia.
In relation to geological time, we see that is divided into millions of years. Thus, geological time spans three eons: the Archaic period, the Proterozoic period, and finally the Phanerozoic period. The latter is the most recent and began over 500 million years ago when the first living beings appeared on Earth.