A goniometer is an instrument that either measures angles or allows an object to be rotated to a precise angular position. The term goniometry is derived from two Greek words, gonia, meaning angle and metron, meaning measure.
There are many types, each specialised for its particular application.
The contact angle goniometer was invented by Dr. William Zisman of the Bethesda Naval Research Lab and the first of this type of instrument was built by ramé-hart during the 1960's. Currently, ramé-hart instrument co. builds not only classic manual contact angle goniometers based on Dr. Zisman's design, but also automated instruments that use cameras and software and are used not only for contact angle and surface energy applications, but also surface tension using pendant drop, sessile drop, and myriad other techniques. The manual contact angle goniometer uses an eyepiece with microscope. The newer generation of instruments use a camera and software to capture and analyze the drop shape.
Goniometers are used in crystallography for measuring angles between crystal faces. They are also used in X-ray diffraction to rotate the samples. Other versions range from devices which measure human joint movement to ones which determine the angle of contact between a liquid droplet and a flat substrate.
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