We know there are scales for measuring large objects, but did you know there’s a scale for measuring tiny ones, too? It’s called an electrostatic force balance, or EFB, and is used to measure the mass of small objects that weigh between 50 micrograms and 20 milligrams. Because the device uses electrostatic forces – think the static charge that occurs when you rub a balloon against your hair – it can be traced back to the fundamental constants in the SI (the modern metric system) through electric