LOUISVILLE, Ky. — News of COVID-19 vaccines and deployments have taken over the headlines in recent weeks, and various numbers have been thrown at us: the efficacy, how many doses are needed, and ...

Hot and cold are measured using a numeric scale called temperature. Temperature scales are how we communicate about the weather, measure safety and comfort and explain the physical world. Using ...

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, ...

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 ...