The scientific world just experienced one of the biggest shake-ups in the history of measurement. The definitions of the seven base units of the SI (AKA the International System of Units) are now completely different from a week ago. Here’s what you need to know.
Whether you’re on your first pair of glasses or your tenth, you may still be put off by phrases like “temple arms” and “lens height,” especially if you’re interested in shopping for your own frames. This visual guide shows you what all those terms mean so you can buy confidently.