Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
Teachers Powered by teachers'domain

Rare Earth Elements

  • Teacher Resource
  • Posted 08.09.12
  • NOVA

In this video excerpt from NOVA's "Hunting the Elements," New York Times technology columnist David Pogue learns about a set of elements commonly referred to as rare earths. Hear how rare earths are often used in technological applications and visit a rare earth mining site to learn more about where they are mined. Discover that rare earths are not really that rare and explore how their atomic structures make them nearly indistinguishable from one another.

Permitted use: Download Download

NOVA Rare Earth Elements
VIEW
  • Media Type: Video
  • Running Time: 4m 18s
  • Size: 15.4 MB
  • Level: Grades 6-12

  • Log in to Teachers' Domain to download, share, rate, save, and match to state standards.

Source: NOVA: "Hunting the Elements"

This media asset was excerpted from NOVA: "Hunting the Elements."

Teaching Tips

Here are some of the main ideas students should take away from this video:

  • Rare earths are a set of 15 elements located near the bottom of the periodic table.
  • Rare earth elements, such as neodymium, are key ingredients in many technological applications. They can be found in things such as computers, cells phones, hybrid cars, and wind turbines.
  • All 15 rare earth elements have the same number of electrons in their outer shell.
  • Rare earth elements have very similar chemical properties and are difficult to separate from each other.

Here's additional information not featured in this video that can be shared with students:

  • The majority of rare earth minerals are mined in China because that country has the majority of mining facilities in operation.

Questions for Discussion

    • Do you think “rare earths” is a fitting name for this set of elements? In what way are rare earths “rare?”
    • What percentage of rare earth minerals comes from China?
    • How do you think limiting the export of rare earth minerals from China would affect the rest of the world?
    • Describe why rare earth elements have similar chemical properties.

Transcript

DAVID POGUE (Technology Guru): The rare earths—fifteen elements located near the bottom of the table.

And in my job as a technology writer, there's one rare earth that interests me more than any other, neodymium.

It's the key ingredient in the world's strongest magnets. They're critical to computers, cell phones, hybrid cars, wind turbines, even tiny ear buds. Without neodymium, we'd be sunk!

So that raises a question: if they're in everything, how come they're called "rare" earths?

The best place to find out is at the source. John Burba is the chief technology officer at Molycorp. He's overseeing a billion-dollar operation to bring this 50-year-old mine into the 21st century.

So how many rare earth mines like this are there in the United States?

JOHN BURBA (Chief Technology Officer, Molycorp, Inc.): One.

DAVID POGUE: This is it?

JOHN BURBA: This is it.

DAVID POGUE: One mine in the United States, and John tells me it's not even fully operational yet.

So, where do rare earth minerals come from in the world?

JOHN BURBA: The majority of it comes from China.

DAVID POGUE: What kind of majority?

JOHN BURBA: Like, 98 percent.

DAVID POGUE: Ninety-eight percent of these minerals come from China?

JOHN BURBA:Yes.

DAVID POGUE: Then he breaks the news that the Chinese government has been limiting the export of these strategically important elements.

Seems like the fate of the free world could be riding on these rocks. I'd better get some of my own while the getting is good.

JOHN BURBA: But look for stuff like this; we'll find out how good a geologist you are.

DAVID POGUE: This reddish stuff?

JOHN BURBA: Yeah.

DAVID POGUE: This is a hunk of, of what?

JOHN BURBA: Barite, barium sulfate…it's got some monazite in it. They are naturally occurring crystals that contain the elements.

DAVID POGUE: So, can I get a few more of these?

JOHN BURBA: Yeah, just look for stuff that, that's similar.

DAVID POGUE: You know what, John? I like these two a lot. I can't decide. It's an either "ore" situation.

So how can I find out which elements are in this hunk?

Molycorp's facility is still under construction, so, to find out what's in my rocks, he suggests I take them to the world's premier rare earth research lab, in Ames, Iowa. We'll be there soon.

I'm dying to know what I've got my hands on: a pinch of praseodymium, perhaps? A whole pound of holmium? A thimbleful of thulium? Or dare I hope, magnet-making neodymium?

If anyone can extract all the precious neodymium from my rocks, it's these guys.

LAWRENCE JONES (The Ames Laboratory): David, I've been expecting you. Good to see you.

DAVID POGUE: David Pogue. How are you?

LAWRENCE JONES: Yes, sir. Yes, sir. I see you brought the ore with you.

DAVID POGUE: I brought this all the way from California.

LAWRENCE JONES: All the way? All right!

DAVID POGUE: I carried it by hand.

LAWRENCE JONES: Uh-huh.

DAVID POGUE: Because you know it's rare earth…

LAWRENCE JONES: It's rare earth.

DAVID POGUE: …ore, and I didn't want anything to happen. I didn't check it. I didn't put it in the overhead.

LAWRENCE JONES: Yeah, okay.

DAVID POGUE: I think I got some beautiful samples.

LAWRENCE JONES: Oh, yeah?

DAVID POGUE: There's this mine in California, the largest one in the United States.

LAWRENCE JONES: Right.

DAVID POGUE: Look at the size of this one.

LAWRENCE JONES: Oh, yeah.

DAVID POGUE: I think this one's my favorite.

LAWRENCE JONES: Oh, yeah.

DAVID POGUE: I thought if we brought it here to Ames Lab, I thought you could do a little chemical analysis on it and tell me.

LAWRENCE JONES: We certainly can.

Well, let's see.

DAVID POGUE: Yeah, watch out with that…

LAWRENCE JONES: We'll take your favorite one and…

DAVID POGUE: Watch out with the hammer. What are you…?

LAWRENCE JONES: See? Oh, yeah, there we go. That's a good piece right there. That's all we're going to need for the chemical analysis, so the rest of this we'll just…

DAVID POGUE: Yeah, but…

LAWRENCE JONES: …throw it right here, in the trash.

DAVID POGUE: But, but that's, that's rare ear-, ah! California!

The truth is rare earths are not rare. They're just notoriously hard to separate. The problem is at an atomic level, the rare earth elements all look weirdly alike. Moving from element to element, along a row of the periodic table, adds a proton to the nucleus and an electron to the outer shell, but in the rare earths, the new electron disappears into an unfilled inner shell. The result? Fifteen atoms that all have identical outer electron shells, making them virtually indistinguishable chemically.

But what about my rocks?

LAWRENCE JONES: Okay, David, the ore that you brought us, the rocks that look like this, we analyzed those, and this is what we found: we found major components of cerium, lanthanum and praseodymium, but no neodymium.

DAVID POGUE: Apparently, my rocks are neo free.

Resource Produced by:

WGBH Educational Foundation

Collection Developed by:

WGBH Educational Foundation

Collection Credits

Collection Funded by:

U.S. Department of Energy



Related Resources

  • Hunting the Elements

    A two-hour special from the producers of "Making Stuff"

  • Developing the Periodic Table

    This video excerpt from NOVA's "Hunting the Elements" looks at how early chemists developed the periodic table.

  • NOVA Elements

    Explore the periodic table, and build atoms and molecules in this web edition of the NOVA Elements iPad App.

  • Magnetic Fish Hooks Save Sharks

    A chance discovery that sharks avoid rare earth magnets may help protect them from over-fishing.