What is Mill (grinding)?
:For other uses see ''[[Mill (disambiguation)]]'' [[File:Rembrandt van Rijn - The Mill - Google Art Project.jpg|thumb|[[Rembrandt van Rijn]]]] A '''grinding mill''' is a [[tool]] that is designed to break a solid material into smaller pieces. There are many different types of grinding mills and many types of materials processed in them. Small mills can be powered by hand, such as a [[mortar and pestle]] or a pepper grinder. Large grinding mills were usually powered by [[working animal]]s, wind ([[windmill]]) or water ([[watermill]]) in the past. In the 2000s, most large grinding mills are powered by [[electricity]]. ==Types of grinding mills== ===Mortar and pestle=== [[File:Coffee grinder.jpg|thumb|upright|hand mill for grinding coffee]] People who need to grind a small amount of a food, such as spices or grain, for their own cooking often use a hand-powered [[mortar and pestle]] or a hand-powered grinder, such as a pepper grinder. In the 2000s, many people also used [[electricity|electric]]-powered grinding mills. These [[kitchen appliance]]s have a metal blade that grinds the food into small pieces. Electric-powered grinding mills are often used for grinding nuts or coffee. ===Grain mills=== For thousands of years, humans have ground their grains (such as wheat or corn) into flour using grain mills powered by animals (such as [[oxen]] or [[horses]]), wind ([[windmill]]s) or by running water from a stream or river ([[watermill]]). In the 2000s, most grain mills are powered by [[electricity]]. ==Mechanical process== After grinding the state of the [[solid]] is changed: the [[grain]] size, and the grain shape. Also, there may be more or less crushing. For [[process engineering]], several things are important: increasing the surface area of the solid; making the solid have wanted grain size; and pulping the material to the desired state (squishing it). <gallery> Image:KinderdijkMolens02.jpg|A [[windmill]] has large sails that use the force of the wind to turn heavy stone grinding surfaces, to grind grain