The subject area Devices and Tools describes significant developments in the use of such items within the realm of energy. The entries in this section range from the earliest evidence of use of stone tools by the predecessors to modern humans, up to the development of solar-powered nanomotors within the past decade.
The earliest tools relied solely on human energy, later to be supplemented or replaced by animal power. By the early Middle Ages various devices would be in use to increase the efficiency of animal power, such as the plow, the spoked wheel, and the stirrup. Human power was amplified by the use of so-called simple machines, such as the screw, lever, wedge, inclined plane, and geared wheel (cogwheel).