Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

For more than two centuries, the measurement of horsepower has been traced back to James Watt’s claims about draft horses, yet few questioned whether those numbers were accurate. In this experiment, ...

When an inventor has a unit of measurement named after him, it's clear his work had more than a small impact on scientific and industrial progress. So it was for James Watt, whose Watt engine is often ...

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in ...