• Always use the proper tools for measurements.measurement of diameter image by Witold Krasowski from Fotolia.com
  
  Torque is the amount of force applied on an object multiplied by the distance from the center of mass of the object. In mathematical terms, this is force times radius, also known as the moment arm. Torque is also known as the moment of force, or simply as "moment." Just as how a force can move an object (by pushing or pulling), a torque can rotate an object about an axis. Measuring torque can be accomplished using a force meter and a ruler, a strain gauge or a torsion meter.
  
  

Force Meter and Ruler

• The simplest way to measure the amount of torque is by using a force meter and ruler, or any other length measuring device, such as a yard stick. This is a crude method, because it measures torque in an indirect way by measuring the force applied and the moment arm. The force meter needs to be attached to the location where the force is applied, and the location of the center of mass of the object needs to be known so that the torque can be calculated by multiplying the force with the moment arm.
  
  

Strain Gauge

• A strain gauge is an electronic device that is printed on a semi-flexible wafer and then attached directly to the surface of an object. When the object flexes (due to torque), the resistance in the circuitry of the strain gauge changes. From this change in resistance, a computer program attached to the strain gauge can output torque measurements.
  
  

Torsion Meter

• A torsion meter is a specialized form of a strain gauge in which several strain gauges are set in a configuration to measure torque directly. The torsion meter is connected to a computer with a program that captures the electrical readings, which are then converted into measurements of torque.