How Do We Know about Layers Deep within Earth?
ES0402  Modeling Internal Structure

You just observed that P and S wave behavior is different in solids and liquids. P waves travel through both solids and liquids. S waves travel through solid material, but they cannot travel through liquids. This difference can be used to tell which parts of Earth’s interior are solid and liquid.

Another difference in P and S waves is their speed. You saw that P waves travel faster than S waves. Also, P waves travel faster through solids than through liquids. Thus, the difference in the amount of time it takes for P and S waves to travel through Earth’s interior provides information about the type of material through which the waves pass.

Jennifer Loomis, TERC
To understand how P and S waves indicate Earth’s interior structure, you’ll analyze visualizations of P and S waves moving through several model planets.

  !   Click the image to begin the animation.

5. Based on the pattern of the P and S waves, what type of material is this planet made of?


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