We use vernier caliper to measure small length such as diameter of rod , internal diameter of a tube the depth of a cavity or the thickness of a plate, that which cannot be measured accurately by meter rule.
digital vernier caliper
parts of the Vernier caliper.
A Vernier caliper has two ,big and smaller jaws that are used for measuring external diameter, and internal diameter of objects respectively. Some models also have a depth gauge. The main scale is fixed in place, while the Vernier scale is the name for the sliding scale that opens and closes the jaws.
Vernire caliper can measure to an accuracy of 0.01cm or o.1mm.
The venire caliper has also tow scales, main scale M, and venire scale V, the venire scale which is smaller, is added to main scale to give the fraction of the smallest division on the scale during measurement
The main scale may be calibrated in millimeter, centimeter, meters or even in inches, while the venire is 1/10 of the smallest division in main scale , that means that the vernier is obtained by dividing the smallest division in the main scale into ten . For example if the smallest division in main scale of a vernier caliper is 0.1cm, then the vernier scale is 0.1cm divide by ten ( ie 0.1/10 = 0.01cm), which is equal to 0.01cm
How to measure with vernier caliper
Note that each scale in vernier caliper red just like ordinary meter rule. When you take your measurement with venire caliper , do it at where the main and venire scale coincide, so after taking the reading of main and venire scale respectively, add them together and the sum gives you the actual reading on the vernier caliper.
For example if the reading in the main and venire are 4.3cm and 0.07cm respectively, this means that the actual reading is 4.3 + 0.07= 4.37cm.