Still images and related media

Assess and apply your learning
Side-by-side comparison of composition vs. mechanical properties
    • Whole Earth
    • Near surface
Layers by composition
    • Whole Earth
    • Near surface
Layers by mechanical properties
    • Whole Earth
    • Near surface
Formation of the crust, mantle and core
i.e. planetary differentiation

Related topics
    • Plate tectonics
    • Isostasy

Questions for thought

  1. What are the known layers of the Earth based on composition? on response to stress?
  2. What is the difference between a layer based on composition vs. response to stress?
  3. In the context of rocks, what does the word "stress" refer to?
  4. Which layer is a subset of the other - crust or lithosphere?
  5. Which layer makes up a "lithospheric plate" - crust or lithosphere?
  6. How does the composition of rock change across the lithosphere/asthenosphere boundary?
  7. Is the mantle molten?
  8. Does lava that appears at the Earth's surface originate in the molten outer core?
  9. How long have the Earth's layers existed?
  10. Was the interior of the early Earth more or less homogenous than it is today?

The meanings of words

  1. What does the word context mean?
  2. How does stress differ from strain in the context of rocks?
  3. How are the meanings of stress and strain in the context of people vs. rocks similar and different?
  4. What is a mechanical property of rocks?
  5. What is a chemical property of rocks?
  6. What is the meaning of the word homogenous?
  7. Can you think of an antonym for the term homogenous?
  8. Why are cartons of milk labeled as homogenized?


  1. Other references may refer to the layers recognized on the basis of response to stress as "mechanical layers."