Howardites

The answer sheet for the worksheet Iron meteorites and their hidden patterns. Each answer comes with the reason, so it can be used to mark or to go over the questions with the class.

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Start here: Explorer · Ages 10 and upAnswer sheet for teachers

Answers: Iron meteorites and their hidden patterns

  1. A: An iron sulphideTroilite is an iron sulphide, often found as nodules in irons along with graphite.
  2. C: HexahedriteHexahedrites are low in nickel, nearly all kamacite, and often show Neumann lines.
  3. B: Melting let the dense metal sink inwardsWhen an asteroid melted, its heavy metal sank to the middle and formed a core.
  4. A: Gibeon, a fine octahedriteGibeon from Namibia is a fine octahedrite, and the giant Hoba meteorite is an ataxite.
  5. C: By the width of their kamacite bandsOctahedrites are called coarse, medium or fine according to how wide their kamacite bands are.
  6. False: the right answer is Kamacite is low in nickel and forms broad bandsLow-nickel kamacite makes the broad bands, edged by thin borders of nickel-rich taenite.
  7. True (We cannot sample Earth's core directly)We cannot sample Earth's core directly, so asteroid cores are the closest examples we can study.
  8. Shock (accept any answer with the same meaning)Neumann lines are fine parallel lines produced by shock, for example from impacts.
  9. Its bands follow the faces of an eight-sided shape (accept any answer with the same meaning)An octahedron has eight faces, and the bands in an octahedrite run parallel to them.
  10. Octahedrite (accept any answer with the same meaning)Octahedrites have roughly 6 to 13 per cent nickel and show a Widmanstätten pattern.

Task

Answers will vary. The task comes from the lesson: Look at pictures of an etched iron meteorite and try drawing the pattern. Notice how the bands cross at a few set angles. Can you find the thin bright borders of taenite?

Look for work that uses the key words correctly and gives a reason for each point.

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