Chapter 1 (cont.): Unit of Measurements

Posted by concettinasfienti on April 22, 2015

(Picture Source: Wikipedia)

Almost every physics course begins with the introduction of fundamental units of measurements. With such a term what we mean is, as Wikipedia puts it: ” a definite magnitude of a physical quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of measurement.”

We are speaking namely of kilograms (unit of measurement of mass), seconds (time), meters (length), just to mention the most common ones. Things seems to get boring with physics all of a sudden. Why does not need to understand something like this in the journey through the universe and is there really something to understand about them?

Well, “A journey of a thousand miles begins with…” a good pair of shoes!

Like in everyday life also in physics we need to establish standards for all other sorts of things: to help with communication, and cut down on confusion. Knowing the units of measurement that correspond with a number can give you so much more information than a digit sitting there by itself. In science serves as the supporting pillar upon which a number rests.

The task of giving a quantity its proper unit of measurement is therefore as fundamental as giving a person a birth name: would you argue that it is superfluous? Indeed this person will exist, no matter what his name is or whether his parents have given him a birth name in the first place. Within a social context everything else but the bare existence though is connected with his name. It is through the name that we can assign all sort of stuff (character, behavior etc) to the person (I might agree that this argument can be taken also as purely philosophical).

As with birth names and nicknames so is with unit of measurements. My name is Concettina and my usual nickname is tt. I am 1.80 m tall and my length has also a nickname: I am 6.e-9 light seconds tall (a light-second is the distance light travels in an absolute vacuum in one second).

This example brings us to the second question, whether or not there is something to understand about them, the answer is of course yes. We need to understand how unit converts to one another, how some of them are derived from the one which are fundamental and what they actually mean.

Only then we can be sure that in our journey through nature, we will be actually able to measure something meaningful!

What’s in a name? That which we call a rose by any other name would smell as sweet.” (W. Shakespeare). Well, with meters, seconds and friends they will surely NOT smell at all if we call them by other names!




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