James Watt

The Scottish inventor James Watt improved the design of the early steam engine, ensuring that it could be used successfully throughout industry. He refined the steam engine designed by the English engineer Thomas Newcomen (1663–1729), and made it more efficient.

Watt's work helped to bring about the industrial revolution in Britain. The new Watt steam engines provided much of the power for Britain's industries during the 1800s. The watt (W), the unit of work or power, is named for James Watt. The power of most electrical devices, such as light bulbs and heaters, is rated in watts.

James Prescott Joule

The English physicist James Prescott Joule is famous for his experiments with heat. He discovered that the various forms of energy – mechanical, electrical, and heat – are basically the same and that one form can be changed into another. Joule's research was so significant that his name was given to a unit of work or energy, the joule (j). Joule did not have any formal academic training or an academic post. However, he worked with some of the leading scientists of the time, including the English chemist John Dalton (1766–1844), and the Scottish physicist Lord Kelvin (1824–1907).