Welcome to ProEdify TEAS Prep, this is part one of the Lesson on Units of Measure.
In this video, we will discuss various units of measure and we'll also introduce the SI system of measurement.
To begin, let’s define what a measurement is and what it actually means to measure something.
Well in science, a measurement is the assignment of a numerical value to an objects’ physical property.
Measuring physical properties, such as length, volume and density is very common.
For example, you might want to know the length of a line, the volume of a sphere, or the density of a liquid.
Whenever we take measurements, we also have to assign units to the numerical
quantity, in order to convey the relative size or magnitude of the property in question.
For instance, if I said the length of my shoe was 10 you wouldn’t actually know how long my shoe was
because there would be no context for what the 10 represents.
In fact, this measure would only make sense if the number 10 had a unit of measure to go along with it.
So what is a unit of measure?
In order to have accurate and reproducible ways to define magnitudes
of length, volume, density, etc.,
scientists have developed various systems of measure.
These systems are made up of units of measure
which are basically standardized amounts of various physical quantities.
The SI system is the international system of measure used by scientists.
It is a very comprehensive system with many units of measure.
However, we will only need to cover a few of these units in order to prepare for the TEAS.
The fundamental physical properties you will need to know for the TEAS are as follows:
Mass, Length, Temperature and Time.
You can see that for each property there is a mathematical label, which is used in formulas,
and the actual name of the corresponding SI unit or measure.
Please feel free to pause the video and familiarize yourself with the information on this chart.
Notice that the chart refers to these units as “base” units, because they help to
define more complex units, which are called “derived units.”
For example,
Area is a physical property that uses a unit called “meters squared”.
Since meters squared, requires the meter in order to be defined,
it is considered a derived measure, or unit.
Let’s walk through an example
that will illustrate how the meter is used to define Area in meters squared.
If we take a line that is 2m in length,
and then create a square from 4 of these same lines,
we can find out the Area or 2 dimensional space that this square occupies
by squaring the length of the original line.
We’re not going to talk about the math concept of squaring in much detail here,
but just know that in essence, we are multiplying a base length measurement
by another base length measurement.
Which is 2 meters times 2 meters.
And this, results in an entirely new derived unit called meters squared.
Now that we understand a little bit about derived units, let’s take a look at some
important ones that you will need to know for the TEAS.
By looking at this chart, you might have noticed
that things like Mass per Unit Volume and Meters per Second
are also considered units of measure,
just like the “Liter” or the Newton.
The only difference is that some measures,
such as Liters and Newtons, have a unique unit name
while other measures have unit names based on their mathematical formula.
Also note that some derived units require other derived units to be defined,
which is the case with both Density and Pressure.
Don’t worry if you are a little confused about these measurements and what they are used for.
We will discuss them in more detail as they are used throughout the series.
This concludes our discussion on the SI system of measurement.
Thank you for watching!