Transcript:

The word energy is one of those words that leaked out of the classics during the renaissance and into English in the late 1500s. It goes back through Latin to Greek where ergon meant “work,” so that energy is what is what “does the work.” Apparently the word goes back far enough that Aristotle used it and he was born 384 BCE.

When it first became an English word it didn’t refer, as it does now to the kind of energy that causes climate change, but to the—as the Oxford English Dictionary puts it—“force or vigor of expression” of a speech or piece of writing. Of course that kind of definition still applies, as it would to how enthusiastically you go about blogging or playing tennis. But by the beginning of the 1800s the word energy was being applied in very specific terms to principals in physics.

It still is. You can measure energy in so many joules which is so many watts per second. Both of these units of measurement, joules and watts are named—as are a bunch of other units—after people who were smart enough to help figure out how the science behind it all worked.

A joule of energy is named in honor of James Joule who laid the foundations for the first law of thermodynamics.

Whoa, I can hear people tuning out all over. But wait, I’m not going technical on you.

The idea is simple. If you add energy to something it’s going to get hotter, or else you’re going to have to get some of that energy out of there by making the thing do some work. Put electricity into an electric motor it turns the wheel; jam the wheel and stop it doing work—meltdown.

The guy who figured this out didn’t do it because he was a famous scientist doing work in some ivory tower lab. James Joule did it because he thought it was fun, and he hoped he could make some money at it. As a kid James had been fascinated by science experiments and although electricity was still in its early days he delighted in giving electric shocks to his brother and the household help.

Later he went to work in his dad’s brewery and was trying to do what we would call a business case for replacing the steam engines that moved things around the place, with electric motors. He did experiments but the lab equipment was pretty rudimentary back then and he was happy if his results were within ten percent of what he predicted they should be. He tried to publish his findings and theories but the ivory tower science establishment blew him off. They had another theory that heat was some sort of gas, and they were sticking with it. They heard him out a few times but saw him as a bit of a back-country amateur. But as evidenced by the fact that the International System of Units uses his name as the name of the official unit of energy, his ideas ended up being the correct ones.