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For other uses of the term Machine, see Machine (disambiguation)
A machine is any mechanical or organic device that transmits or modifies energy to perform or assist in the performance of tasks. It normally requires some energy source ("input") and accomplishes some sort of work.
People have used mechanisms and machines to amplify their abilities since before written records were available. Generally these devices decrease the amount of force required to do a given amount of work, alter the direction of the force, or transform one form of motion or energy into another.
The mechanical advantage of a simple machine is the ratio between the force it exerts on the load and the input force applied. This does not entirely describe the machine's performance, as force is required to overcome friction as well. The mechanical efficiency of a machine is the ratio of the actual mechanical advantage (AMA) to the ideal mechanical advantage (IMA). Functioning physical machines are always less than 100% efficient.
Modern power tools, automated machine tools, and human-operated power machinery complicate the definition of "machine" greatly. Machines used to transform heat or other energy into mechanical energy are known as engines.
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A tool is a device that provides a mechanical or mental advantage in accomplishing a simple machine, or a combination of them. For example, a crowbar simply functions as a lever. The further out from the pivot point, the more force is transmitted along the lever.
Philosophers once thought that only humans used tools, and often defined humans as tool-using animals. But observation has confirmed that monkeys and other animals, mostly primates, but also some birds (ravens, for instance), and sea otters can use tools as well. Later, philosophers thought that only humans had the ability to make tools, until zoologists observed birds[1] and monkeys[2][3][4] making tools. Most anthropologists believe that the use of tools was an important step in the evolution of mankind. Humans evolved an opposable thumb (useful to hold the tools) and an increase in intelligence (aiding in the use of tools).
Most tools can also serve as weapons, such as the hammer and the knife. Similarly, people can use weapons, such as explosives, as tools.
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Toy tools make popular playthings. Some simply consist of a cheap or small version of the real thing, such as a shovel and bucket to use on the beach or in a sandbox. Others are less functional, e.g. a dull plastic knife, or not functional at all.
In computing, the term \"tools\" can also apply to software programs that assist people doing work on computers, such as Computer Aided Software Engineering tools, Lint programming tool, software or web-based collaborative tools, software development tools, programming tools.
Stemming from a double-entendre where a "tool" is a phallus; this became a popular word in the 1990's. Individuals may be described as "tools", as an insult meaning that someone is a klutz or easily taken advantage of.
Many tools or groups of tools serve to perform one or more of a set of basic operations, such as:
Use of tools started at the beginning of the Stone age. Humans have fabricated knives, amongst the oldest tools, since that time.
Mechanical devices, though known to Alexandrian Greeks, experienced a major expansion in their use in the Middle Ages with the systematic employment of new energy sources: water (waterwheels) and wind (windmills).
Machine tools occasioned a surge in producing new tools in the Industrial revolution. Advocates of nanotechnology expect a similar surge as tools move down-scale.
WikiProject Metalworking: This article is part of Metalworking hand tools.