Video Transcript
Which of the measuring tools shown is a set of vernier calipers? (A), (B), or (C).
To begin, let’s recall that a vernier caliper is a type of tool that’s used to
measure lengths with a resolution of less than a millimeter, which allows us to more
accurately measure small lengths than we could using a standard ruler.
To measure an object, we align it with the jaws of the caliper. Recall that vernier calipers have two different sets of scales along their
length. When we slide the caliper jaw into position, a sliding scale, called the vernier
scale, slides into place. We then combine the reading from each scale to reach a final measurement value.
Knowing this, let’s take a look at the answer options given to us. Option (A) shows a familiar, everyday object used to measure length: a ruler. Rulers and vernier calipers are very different tools. And so we know that option (A) isn’t what we’re looking for.
Next, let’s look at option (B). Here, we see a device with two sets of scales along its length. One scale slides along with a jaw used for aligning the object that we want to
measure. This description fits that of a vernier caliper. So it seems that option (B) is the correct answer.
Now moving on to option (C), we see another device that’s more complex than a ruler
and that has two different sets of scales. However, the scales are oriented differently than those that we saw in option
(B). Here, one scale is oriented along the length of the device, and the other is on this
rotating piece. And instead of having a sliding jaw like a caliper, this tool has a piece that needs
to be rotated like a screw in order to tighten and secure the object to be
measured. Thus, we can see that this is not a set of vernier calipers. Rather, this is a measuring tool called a micrometer.
Therefore, we know that answer choice (B) is correct because it shows a set of
vernier calipers.
