You spin me right round, baby, right round, like a windmill, baby, right round round round.
Featured above: The ancient windmills of Nashtifan. They kind of look like turnstiles. They’re a very different design from what we’re accustomed to, based on drag rather than lift.
Once again, show notes will be coming soon — sorry about that! — but I did promise a reason to get your old CDs out of your closet: The data is rotting off of them. CDs aren’t a very stable medium, especially the rewritable kind. You should check anything vital now, to make sure it still exists!
It’s a familiar story by now: A chemist had a sample of a supposedly pure rare earth, but he was pretty sure there was something else lurking inside. This time, the chemist was de Boisbaudran, and the rare earth was holmium.
He took his holmium oxide and dissolved it in acid, then added a little ammonia, and analyzed the result to see if he’d been successful. It took him over thirty tries, but eventually, he did find evidence of a new element.
Because it had been such a pain, he named the new element after the Greek word root “dysprositos,” which means “hard to get.”
It’s fairly notable to be known as the one that’s difficult to isolate among a chain of elements whose name means “hidden ones,” and there might have technically been better contenders for the title. But let’s not complain — at least this one’s not named after Ytterby.
You’re listening to The Episodic Table Of Elements, and I’m T. R. Appleton. Each episode, we take a look at the fascinating true stories behind one element on the periodic table.
Today, we’re playing hard to get with dysprosium.
Another lanthanide, another highly specialized application of quirky magnetic properties.
Four episodes ago, we discussed the Curie Point. At that temperature and above, a material loses its magnetic properties. Considering magnets are critical to the operation of motors, electrical generators, and other high-temperature environments, that can turn into a pretty significant problem.
Dysprosium to the rescue. When element 66 is added to the mix, it can help a magnet stay magnetic at much higher temperatures than normal. This has landed it a job in some important technology of the 21st century. An electric car contains around 100 grams of dysprosium, but there’s a machine that uses six hundred times as much and is part of a much, much older mechanical lineage: The wind turbine.1
Humans have been harnessing wind power for a very long time. It’s just too obvious a source of energy to pass up. For thousands of years, we’ve hoisted mainsails into the wind as we moved across the globe,2 but the first stationary wind machines date back to 1,700 BCE. 3
The ancient Babylonian King Hammurabi made history for his written legal code, which contained such classics as, “Anyone caught committing a robbery shall be put to death,” and the timeless crowd-pleaser, “If a man destroy the eye of another man, they shall destroy his eye. If one break a man’s bone, they shall break his bone.”
Some ancient windmills still survive in that part of the world. On a hill above the Iranian town of Nashtafan, two dozen structures creak and sway as they capture the wind with their vertical wooden fins, turning stones that mill grain into flour, just as they have continuously for the past thousand years.7
Nowadays, the entire operation is overseen by only one man, Ali Muhammed Etebari. He has watched over the site for thirty years, but he’s getting older, and he has no assistant or apprentice. The town’s children, he says with a laugh, are more likely to “spoil it and break everything.”8
Windmill technology traveled west, or more likely, was invented independently in Europe around the 1100s. There the technology found its most famous uses; namely, as something for Don Quixote to tilt at, and to drain the polders in the Netherlands.
That second one is more impressive than it might sound at first. The polders are the largest land reclamation project in the world. In 1986, the Netherlands added a new province to their nation, Flevoland, which had previously been entirely underwater. Its residents will happily tell you, “God made the Earth, but the Dutch made the Netherlands.” And so fertile is this new land that the Netherlands is the world’s second-largest exporter of food in the world, after the United States. All thanks to the power of windmills.9
And that was all before electricity entered the picture. That didn’t happen until 1887, when electrical engineer James Blyth illuminated his holiday home in Marykirk, Scotland, using the power of a single windmill. He offered its use to the local village, so its residents could light their streets, but they declined. Electricity, they said, was “the work of the devil.” Blyth found a more receptive audience among the caretakers of the Montrose Lunatic Asylum, where he installed a generator that provided electrical power for thirty years.10
Around the same time, Charles Brush developed a similar technology in Ohio, and his machines became popular all the way up the eastern seaboard. Sadly, wind energy couldn’t quite compete with cheaply generated coal power, so wind turbines were limited to small-scale, local power generation for the next century.
Now, as climate change makes fossil fuels an increasingly irresponsible source of energy, wind turbines offer a much cleaner alternative that’s enjoyed a hundred years of incremental improvements to its efficiency and aesthetics. Around 4% of the world’s energy is generated by wind, from machines anchored in the shallow waters of the ocean, onboard floating platforms, and even flying several miles high in the atmosphere.
Wherever they’re located, they pretty much all depend on a fair amount of dysprosium to get the job done. In fact, there’s some worry that it might be a little too good at its job. Dysprosium is one of the few rare earths that actually is somewhat rare. It’s a little too expensive to make widespread deployment practical, so researchers are on the hunt to find a cheaper, more plentiful substance to take its place.11 12
So if you’re hoping to get your element sample from a wind turbine, better to do so now, before the technology gets improved beyond our usefulness.
There is another technology that made occasional use of dysprosium, and this one’s a little more attainable: It was sometimes one of the metals that formed the dyed and reflective data layer of a rewritable CD.
The way those things worked was kind of amazing. Back in the day, when you were burning a CD, you really were burning a CD. The laser would carve microscopic pits into the alloy that it could later read as information. And when it was being wiped, the laser would hear that metal to a slightly lower temperature, just hot enough to even everything out, so it could be written over once again.
The problem, of course, is that CDs aren’t very widely used anymore, whether they’re rewritable or not. If you still have a spindle of them taking up space in the back of some closet, then you might be in luck. If not… well, it appears that element 66 is exclusively found as a component of obsolete technologies, which really does make it hard to get.
Thanks for listening to The Episodic Table of Elements. Music is by Kai Engel. To learn why you probably should dig those old CDs out of your closet, visit episodic table dot com slash D y.
Next time, we’ll reunite with dysprosium’s other half: holmium.
Until then, this is T. R. Appleton, reminding you that all this came after the discoveries of samarium and gadolinium, so apparently de Boisbaudran felt like he had sufficiently atoned for the whole gallium affair.
- The Elements Of Power: Gadgets, Guns, And The Struggle For A Sustainable Future In The Rare Metal Age, p. 138. David S. Abraham, 2015.
- The Austronesians: Historical And Comparative Perspectives, p. 143-145. Peter Bellwood, James J. Fox, and Darrell Tryon, 20016. Just one example, countless cultures did this, of course.
- Historical Development Of The Windmill. Dennis G. Shepherd.
- Wind Power Plants, Historical Development Of Windmills. Robert Gasch and Jochen Twele, September 7, 2011.
- The Generation Of Electricity By Wind Power, p. 7. Edward William Golding, 1955.
- Astonishing The Wild Pigs: Highlights Of Technology, p. 119. Lucien F. Trueb and Fred A. Stuber, 2015.
- National Geographic, Iran’s Centuries-Old Windmills May Soon Stop Turning. Brian Clark Howard, January 13, 2017.
- Atlas Obscura, Nashtifan Windmills. Elliot Carter.
- ThoughtCo., How The Netherlands Reclaimed Land From The Sea. Matt Rosenberg, updated September 9, 2019.
- The University of Edinburgh, Notable Alumni: James Blyth (1839 – 1906).
- Phys.org, Scientists Create Cheaper Magnetic Material For Cars, Wind Turbines. Laura Millsaps, April 24, 2015.
- ScienceDaily, New Alternatives May Ease Demand For Scarce Rare-Earth Permanent Magnets. April 2, 2019.