Powered the Industrial Revolution
Scottish engineer (1736-1819) whose steam engine reshaped the world.
He didn't invent the steam engine, he made it actually work — adding a separate condenser that quadrupled its efficiency. The unit of power, the 'watt,' is named for him, and he coined 'horsepower' to sell his machines.
James Watt is one of the historical characters you can play as in Rubicon, a trivia game where you answer in your own words and an AI judge reads what you meant. James Watt is filed under Technology & Engineering, and is strongest at Technology & Engineering.