Watts are a common way to measure electricity, whether it’s the 60 watts in a standard lightbulb or the 1.21 gigawatts needed for Marty McFly to go back to the future. But the term “watt” isn’t just some scientific mumbo jumbo — it’s the last name of a prominent 18th-century inventor, James Watt. This scientist was also known for revolutionizing the way steam engines operate, making them run more efficiently. So how did his name come to be so intertwined with measuring electricity?
In 1882, at the 52nd meeting of the British Association for the Advancement of Science, more than six decades after Watt’s death, engineer Carl Wilhelm Siemens proposed “watt” as a unit to measure electrical power. He noted that many other scientific terms were named after leaders in the field, and thought James Watt would be a suitable namesake for this new unit given his contributions to mechanical power, even though his innovations weren’t directly connected to electricity.
In 1948, the watt was redefined as a specific measurement of one joule per second — the joule being another unit of electrical energy. In 1960, the word was added to the International System of Units, after it was adopted at the 11th General Conference on Weights and Measures. It remains the primary unit for measuring power in most electrical devices today.
Other terms in the field of electricity are named similarly for historic figures, including “volt” (“a unit of electrical potential”). It was named for Italian physicist Alessandro Volta, who’s often credited as the inventor of the electric battery. Today, “battery voltage” explains the potential power of a battery. The ohm, a unit of measurement for electrical resistance, was named in 1861 for German physicist Georg Ohm, who spent his life studying the current and potential of electricity.
