If scientists had sacred objects, this would be one of them: a single, closely guarded 137-year-old cylinder of metal, housed in a vault outside of Paris. It is a prototype that precisely defines a ...

In prehistoric times, not much needed to be measured. You ate what you found and lived where you could. The advent of agriculture and civilization, however, necessitated a way for people to measure ...

Wondering why the United States measures things in inches and pounds? The answer will definitely surprise you All countries use the metric system to varying degrees. Most of the world has adopted the ...

Nick van Remortel demystifies natural unit systems — and advises what to do when you see a mass expressed in GeV. Several unit systems for describing the natural world exist. The International System ...

The SI system, adopted in 1960, provides a globally consistent framework for measurements. Learn about this International System of Units (SI) with a comprehensive list of all SI units and their ...

The United States is one of just three countries that "prefers" imperial measurements over the international metric standard. The motivation why has less to do with official policy than you might ...