The vernier scale is a device that is used for
gaining an extra decimal point in the measurement. A diagram is shown in Figure 1. To find
the size of the object being measured you read:
the zero position of the vernier 14.9
and a bit
then the line on the vernier scale that matches a main scale line as closely as
possible in this case line 3
The dimension of the object is then 14.93
units.
Vernier scales of the type found in most school laboratories are usually used to
measure objects up to a few centimetres across and to an accuracy of +/- 0.1
mm.