### Video Transcript

What is the length of the object
being measured by the vernier caliper in the diagram?

We are measuring the length of this
object when it is placed within the jaws of the caliper, which means we’re measuring
its outer dimensions. The first step to measuring an
object within the jaws of a vernier caliper is to read its main scale, located on
the side of the caliper itself. We take a measurement from this
main scale and combine it with the vernier scale, which is located on the caliper’s
bottom jaw. When these scales are used
together, they can measure lengths of up to one-tenth of a millimeter
accurately. So let’s start measuring, starting
with the main scale.

Here is a zoomed-in portion of the
main scale taken from this section right here. Measuring a length on the main
scale is the same as measuring on any other ruler, with the large labeled markings
representing full centimeters and the markings in between those representing
millimeters. However, unlike a ruler, there’s a
discrepancy between where the object actually is in the jaws of the caliper and
where the measurement scale starts and ends. In order to measure an object on
the main scale when in the jaws of the caliper, we always start by measuring at the
zero centimeters’ mark. And we end our measuring at the
zero mark over here, the zero on the vernier scale. So let’s get the measurement for
our main scale.

The largest labeled mark to the
left of the endpoint is two, indicating two centimeters. And then from there, we count the
number of millimeter markings: one, two, three, four, five, six, seven. We stop at the one that is to the
left of the endpoint. This means the measurement is two
centimeters and seven millimeters, or 0.7 centimeters. So, altogether, the main scale
measurement is 2.7 centimeters.

Now that we have this, we can use
the vernier scale to get an even more accurate measurement. The purpose of the vernier scale is
to measure the distance here, in between the millimeter marking and the zero point,
which means that it measures in between the millimeter markings. To see how we do this, we have a
zoomed-in portion of the vernier scale, which is this part right here. We’re not showing the numbers of
the main scale above it because we don’t need them. We just need their lines.

In order to measure on the vernier
scale, we have to find which of the lines on the vernier scale and the main scale
match up the closest. Where the lines match up is where
we’ll find our value for the vernier scale. In this case, we see it is around
the nine mark on the vernier scale because the lines match up there exactly. Now, each of these lines on the
vernier scale, of which there are 10 total, represents one-tenth of a millimeter, or
converted one one hundredth of a centimeter. This means that a nine on the
vernier scale represents nine-tenths of a millimeter or nine hundredths of a
centimeter.

Now that we have our vernier scale
measurement, we just have to combine it with our main scale measurement to find the
total length of the object being measured. And to do this, we just add them
together. 2.7 centimeters plus 0.09
centimeters gives us an answer of 2.79 centimeters. The length of the object being
measured by the vernier caliper in the diagram is 2.79 centimeters.