Description of a Vernier Caliper

Vernier calipers are used to measure internal and external dimensions by sliding the jaws until they touch the object to be measured. The calipers are often calibrated in metric units and can provide a precision to a hundredth of a millimetre (10 micrometres) using the Vernier scale on the lower slider. This simulation demonstrates how to read this Vernier scale.

The inside jaws are used to measure internal dimension of an object shown in green.
The outside jaws are used to measure external dimension of an object shown in blue.
The main scale gives measurement in mm and the Vernier scale adds fractions of a millimeter to the main scale.

Drag the red dot to adjust size the of the caliper jaw. Drag the blue rectangle into the jar to measure its size. The Vernier Calipers Demo model has:

A slider to control width of the object that is being measured.
A check box to that provides a hint how to read the Vernier scale.
A check box to display the current caliper setting.
Radio buttons for external or internal dimension measurements .
A drop down menu of various common vernier scales for additional practice learning how a Vernier scale works.
A reset button to bring simulation back to its original (default) state.