The measure of time. The clock.

I would like to recommend you to watch your video with your students. It shows us a good explanation about the clock and how to learn to understand the time (hours, minutes...)

But why do we need to understand time?

By means of the term "time " The duration of certain events or the separation between two or more of them is measured. In this sense, time is a magnitude related to the field of physics and that basically measures the number of units of measure that have elapsed from an initial state to a final state of something.

Let us then explain and clarify a bit this: for example, suppose I want to walk a kilometer. Then the initial state will be the point from which I will leave, beginning with the walk, while the final state is when I reached the kilometer already walked. That time elapsed between the two states (initial and final) is the separation between 2 events, called Departure and arrival, and which determines how many hours, minutes and seconds I had to use to reach my final state on arrival. In the international system of measurements the official unit of measurement of the time is the second, often abbreviated as  "sec. " But this is not officially so, since it does not belong to a scientific denomination but rather of everyday and colloquial use.

You've also probably heard a lot of times from  "past ",  "present " and  "future ". These are also time and that beyond that they are used in grammar as a way of conjugation of verbs, these three times form part in an arbitrary and consensual way of ordering the facts, according to what moment of time they occupy, ie, taking into account the When they have happened. That is why we know that if something happened yesterday is part of the past, while if we schedule a meeting for next week, we know perfectly well that this is still future time.
Thus, throughout human history, millions of facts have happened and the chronology, discipline within the social sciences, is responsible for establishing methods of study to understand the successions of events.