Watt (W)
The watt (W) is the standard unit of power in the International System of Units, named in honor of James Watt, a Scottish engineer renowned for advancing steam engine technology during the 1700s. Watt’s innovations were pivotal to the Industrial Revolution, making the measurement of power increasingly important. The watt was formally recognized as a unit of power in 1889 and later became part of the global SI system. Defined as one joule per second, it quantifies how quickly energy is transferred or converted. The watt is essential in fields such as electricity, mechanics, and thermodynamics, and it is commonly used to describe the power of household devices, industrial equipment, and energy systems. For larger-scale measurements, units like the kilowatt are used to represent higher amounts of power efficiently.
Horsepower (hp)
Horsepower, symbol hp, is a non-SI unit of power introduced in the late 18th century by James Watt. He developed the term to market his steam engines by relating their work to that done by draft horses. One horsepower was standardized as 550 foot-pounds per second, or about 745.7 watts in mechanical terms. Despite not being metric, horsepower remains widely used in the automotive, aviation, and machinery industries, particularly in the United States and the United Kingdom. Its continued popularity is due to tradition and the practicality of relating to horsepower over abstract units, such as watts. Bridging from non-metric to metric units, the megawatt further illustrates the diversity and scope of power measurement in modern contexts.