Re: How do you use the vernier calipers, and how do we avoid the errors?

Hi Marisa

The vernier is an auxillary scale which slides along the main scale.  It 
is divided into 10 equal divisions so that the 10 divisions of the vernier 
are exactly equal to 9 subdivisions of the main scale.  This means that 
each of the vernier subdivisions is shorter than the mainscale 
subdivisions by one tenth. the very first mark on the vernier is called 
the index.  The index is sometimes marked with a zero.

If the vernier index falls between two of the mainscale subdivisions, you 
simply find the first vernier scale mark that lines up with a main scale 
mark and count the number of vernier marks back to the index.  This 
becomes your fractional reading.  For example, say that the vernier index 
falls between between 1.3 and 1.4 cm on the main scale and you see that 
the third vernier mark lines up with a mainscale mark, the correct reading 
would be 1.33 cm ( the index fell between 1.3 and 1.4 and the first mark 
to line up was number 3 on the vernier). 

One of the main points to remember is that the vernier scale moves and the 
main scale doesn't.

I hope this is helpful
Greg