I consider myself pretty conversant in metric units. I know that 20 kilograms is 44 pounds (double it and add 10%) and that five kilometers is a little over three miles (I’ve, uh, run a lot of 5Ks).

Temperature in America is measured in degrees Fahrenheit, a system named after Polish-born physicist Daniel Gabriel Fahrenheit (1686-1736), who moved to the Netherlands and became one of the pioneers ...

Every once in a while, you may see a temperature in Celsius instead of Fahrenheit. Your car thermometer may revert to the wrong system and you don’t know how to change it, for example. Since almost ...

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, ...