Measurement of Dimension using appropriate instruments.

when you make any statements like 

" Today its 45".

" Distance between Bhopal and Ahmedabad is 587". 

Do not make any sens. To make your sentences appropriate in terms of physics, you need to have units representing that particular quantity. In first sentence temperature is a physical quantity and its unit is Celsius. and for second sentence fundamental quantity is distance and its unit is kilometer. It is very vital when you make any observation, you are listing that observation with proper unit.

We will discuss the liner measurement of dimension in this post.

We have got compass box ruler to measure routine objects in school life. The smallest measurement that can be measured by ruler is 1 mm.

Objects having dimension smaller than 1 mm cannot be measured by ordinary ruler. To get over with the situation one can use vernier calipers. This instrument was invented by French mathematician Pierre Vernier in 1631.

1. Outside large jaws: used to measure external diameter or width of an object
2. Inside small jaws: used to measure internal diameter of an object
3. Depth probe: used to measure depths of an object or a hole
4. Main scale: scale marked every mm
5. Main scale: scale marked in inches and fractions
6. Vernier scale gives interpolated measurements to 0.1 mm or better
7. Vernier scale gives interpolated measurements in fractions of an inch
8. Retainer: used to block movable part to allow the easy transferring of a measurement

Concept of Least Count: The smallest measurement that can be observed by the given instrument is called Least Count (L.C). Obviously for a ordinary ruler the LC will be 1 mm. Mathematically Least Count can be defined as

Main scale division for vernier calipers is 1 mm, it has 10 divisions so least count will be 0.1 mm or 0.001 cm.

How will you use Vernier Calipers for measurement ?

Vernier calipers can be used to measure Length, Breadth, Height, Depth, Diameter and Thickness of given object. The formula for measuring any of above mentioned quantity is

$R = M.S. + (V.S. x L.C)$
here, M.S. = Main scale reading
          V.S. = Vernier scale reading

Now you can use this Vernier Calipers simulator for virtual experience and you can also check your answers.

You can download java applet to your computer from

Ejs Open Source Vernier Calipers

You can test your understanding of the topic with multiple choice questions.

Click here: Test Your knowledge.

Quiz

 Hello friends,

Physics deals with our daily life problems and helps us to find the feasible solutions for those problems. It also explains mystery behind the natural phenomenons occurring around us. Every engineer need to know the concepts of physics as a fundamental science for better understanding any concept of modern engineering. Basic knowledge of physics helps applying engineering tools very effectively and creating innovations. 

One best way to analyse and test the fundamental rules of physics is to perform an experiment. A generalized conclusion can be derived from the experiments which must fulfill all the conditions laid down by the fundamental rule. 

Apart from performing experiments in the laboratory with physical instruments, we can use java based simulations and animations to demonstrate the same concept.