Hydroelectric energy is ultimately solar energy converted through evaporation of water, movement of air masses and precipitation to gravitational potential energy and then to the kinetic energy of water flowing down a slope. That energy was harnessed for centuries through the use of water wheels to drive mills, forges and textile works, before being supplanted by coal-fired steam energy. The unit considers hydropower as a potential source of useable energy. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources...