productivity of food production about tenfold over the technology of the hunter-gatherers. Tools allow one to do things impossible to accomplish with one's body alone, such as seeing minute visual detail with a microscope, manipulating heavy objects with a pulley and cart, or carrying volumes of water in a bucket. The second technological stage was the creation of the machine. A machine (a powered machine to be more precise) is a tool that substitutes part of or all of the element of human physical effort, requiring only the control of its functions. Machines became widespread with the industrial revolution, though windmills, a type of machine, are much older. Examples of this include cars, trains, computers, and lights. Machines allow humans to tremendously exceed the limitations of their bodies. Putting a machine on the farm, a tractor, increased food productivity at least tenfold over the technology of the plow and the horse. The third, and final stage of technological evolution is the automation. The automation is a machine that removes the element of human control with an automatic algorithm. Examples of machines that exhibit this characteristic are digital watches, automatic telephone switches, pacemakers, and computer programs. It is crucial to understand that the three stages outline the introduction of the fundamental types of technology, and so all three continue to be widely used today. A spear, a plow, a pen, a knife, a glove, and an optical microscope are all examples of tools. See also Self-replicating machines in fiction Sociocultural evolution The Automated Society References External links The Evolution of Technology, George Basalla, University of Delaware Technology in society Evolution Technological change