Coins, Dice, and Entanglement

As a kid I loved multiplication. Dividing was hard—because I didn’t know what to do if the remainder wasn’t zero—but I managed to do okay in my tests. It was only in high school that I met the Cartesian product. Tensor products had to wait till my undergrad. Mathematics is full of products: scalar product,…

What is a Measurement?

Stepping on a weighing machine, wrapping a tape around your waist, standing next to a stadiometer, what is common in all these tasks? You're being measured by something. A weighing machine that measures your weight. A measuring tape that measures your waist size. A stadiometer that measures your height. In any measurement, there is an…