Understanding Vernier

Vernier was invented in 1631 by Pierre Vernier. It was invented for the purpose of calculating linear measurement precisely. It consists of two calibrated scales. One is the Main scale and the other one is the auxiliary scale. When observing the measurement in decimal form or fraction then there is a slide of auxiliary scale among the main scale. It is considered one of the advanced rulers because of its capability to give fine and precise units of measurement. It is generally used in science laboratories to calculate distances with accuracy. It is used to calculate both internal as well as external distances. The vernier calliper is of two kinds:

1. Manual calliper

2. Digital Calliper

Least Count of Vernier Calliper

The least count for the vernier caliper is also termed as vernier constant. It can be calculated as the subtraction between a unit of main scale division and a unit of a vernier scale division. Mathematically, it is given by-

VC= 1MSD-1VSD 

If there are total n divisions on the vernier scale which overlap with n-1 divisions of the main scale, then the vernier constant or least count is given by:

LC=(1-n-1n)MSD 

Hence, for the vernier caliper, the least count will be: 0.1mm

Where,

VC= vernier constant

MSD= main scale division

VSD= vernier scale division

LC= least count

Uses of Vernier Caliper

1. It has many medical uses.

2. It is used in science labs.

3. It is used in many industries like steel industries and aerospace.

4. It is even used in educational sectors.

Different parts of Vernier Caliper

1. Main Scale: The scale which runs along the body of the instrument i.e., the vernier caliper is the main scale of the instrument. The main scale is at rest, i.e. it cannot be moved. It is developed with both metric and imperial scales. The imperial scale uses inches as the unit for the measurement and the metric scale uses centimeters as the unit for measurement. The main scale is aligned to the vernier scale. 

2. Vernier scale: This is small in comparison with the main scale and is collateral with the main scale. The opening of the jaws present in the caliper decides the movement of the vernier scale. The main usage of the vernier scale is to give the rightness and perfection to the main scale by dividing its reading into small increments.  

3. Lower Jaws: To measure the outer dimensions the lower jaws are used. These jaws are formulated in such a way to hold the different objects tightly. This jaw is one of the most important attributes of the vernier caliper. One of the lower jaws is attached to the main scale and is fixed to it. While the other jaw is movable and is linked to a vernier scale. 

4. Upper jaws: In comparison in size with lower jaws these jaws are smaller. This jaw is stuck to the top portion of the vernier scale. One jaw is capable of moving while the other is not. To measure the inner dimensions the upper jaws are used such as hollow pipes and jars. The jaws are continued to open till they touch the edges of the body whose dimensions need to be measured. 

5. Depth rod: At the end portion of the main scale, a thin rod is attached which is used to measure the depth of the objects such as jars. It is also known as a depth probe. 

6. Thumb Screw: The main function of the thumbscrew is to move the jaws smoothly and efficiently. It is present at the lower portion of the vernier scale.

7. Lock screw: This part helps to make proper measurements. It fixes the positions of the jaws as soon as the object is fixed firmly in the middle of the jaws. 

Precautions

During the experiment, some kind of small margin error may occur. This can be due to different conditions of the environment or in the procedure adopted. The other reason can be the presence of the default in the tool or the human error i.e., mistakes are done by the humans while calculating or measurement. For accuracy, the errors need to be minimised or resolved.

1. The object should not be seen from an angle. This will lead to parallax error. This error results in taking the wrong measurements. 

2. The observer needs to make sure that all the measurements are in the same units. 

3. The observer should not apply excessive force on the jaws.

Conclusion

Vernier caliper provides the measurement with great accuracy to measure the diameter of the object as well as the width of the object. It is used in many places to upgrade accuracy. It is used by scientists, navigators, and surveyors. The tool consists of two jaws: the upper jaw and the lower jaw. It should be used while considering different precautions so as to minimize the errors. It is also used to calculate the depth of the different objects such as jars. They are available in 2 types: Manual vernier caliper and digital vernier caliper. It is important to calculate its least count for measuring any distance.