How Does a Vernier Caliper Work?

[babita]

WHY do vernier calliper works?

Homework Statement

This is not exactly a problem but i think this is the most appropriate place to post this.
I know how to read a vernier calliper. But i want to know WHY it works. I mean how it gives us the true length.

Homework Equations

The Attempt at a Solution

I have been thinking on it for a long time and I'm not able to conclude why we see coinciding lines.
Also if the 0's on vernier and main scale are marked exactly at the edges wouldn't it be easier to use?
please explain...please don't write just a line or two...i'm going mad

 

[azizlwl]

When you align example 3mm, the lower part align to 0.
You can see that unit 1 of lower scale is 1/10 nearer to main scale
This continue 2->2/10...9->9/10

If you move the vernier scale, the distance moved can be measured from initial position to final position. The one that align must be the easiest to calculate the distance moved.

 

[babita]

well i didnt really understand that...but anyways I've got the logic
We're comparing two lengths, one is having one more no of divisions than the other.
and so on.
(since u already know I'm skipping explanation)