The US is the only industrialized country with no plans to use the metric system. That frustrates scientists, some Vox employees, and former Rhode Island Senator and Governor Lincoln Chafee, who included the metric system in his presidential platform.

But it wasn't always that way. After Congress passed the Metric Conversion Act in 1975, a metric America briefly seemed like a real possibility. And that possibility led to many gloriously corny, often musical attempts to explain to confused Americans just what a meter, a liter, and a gram were.

There's this Schoolhouse Rock–esque cartoon produced by the Office of Education — a forerunner of today's federal Education Department — that helpfully explains Celsius by telling you, "A summer day's about 25, a cold day's minus 3":

There was a superhero team that included "Super Celsius" and "Wonder Gram":

And if you want a much slower-paced — but equally twangy — video, there's this 16-minute version that creates a complicated allegory with two imaginary villages and pulls in Thomas Jefferson as a metric supporter. It really helps everyone that "meter" and "liter" rhyme.

But eventually the metric effort lost steam, and the PSAs got a little less optimistic and joyful. By 1981, the year before the US officially gave up on going metric, the superheroes were gone, replaced by a much more soporific ad of a woman pumping gas: