Chapter 9: Problem 13

The deepest wells and mines go down only a few kilometers. What, then, is the evidence that iron is abundant in the Earth's core? That the Earth's outer core is molten but the inner core is solid?

Short Answer

Expert verified

The abundant iron in Earth's core is evidenced by Earth's magnetic field, which requires a conducting material like iron to generate it. The state of the core is ascertained through seismic wave studies. The liquid outer core is deduced from the absence of S-waves in certain seismic records, as these waves cannot travel through liquid. The solid inner core is inferred from the observed behaviors of P-waves, which speed up and refract upon reaching it, suggesting a shift from liquid to solid due to drastic change in pressure and temperature.

Step by step solution

Explain the Evidence for Abundant Iron

Earth's magnetic field is a significant piece of evidence for an iron-abundant core. The magnetic field is generated by electric currents produced through the motion of conducting material, like iron, in the Earth's outer core. Further backing this is the fact that iron is one of the most abundant elements on Earth, and its heavy mass would naturally lead it to settle in the core during Earth's formation.

Discuss the Differing States of the Core

Understanding that the Earth's core has different states - outer core being liquid and inner core being solid - comes from the study of seismic waves. Seismic waves, specifically S-waves, do not travel through liquids. Observations show that S-waves are absent from the seismic records on the other side of the Earth from an earthquake, which indicates the presence of a liquid outer core that they could not pass through.

Explain the Solid Inner Core

The existence of a solid inner core is inferred through the modification of P-waves (which do travel through liquid). Certain P-waves, upon reaching the inner core, speed up and are refracted due to a drastic change in pressure and temperature, indicating a shift from liquid to solid state. Additionally, the high pressures and temperatures present in the core dictate that even iron, though it would usually melt at surface temperatures, stays solid.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

The deepest wells and mines go down only a few kilometers. What, then, is the evidence that iron is abundant in the Earth's core? That the Earth's outer core is molten but the inner core is solid?

Short Answer

Step by step solution

Explain the Evidence for Abundant Iron

Discuss the Differing States of the Core

Explain the Solid Inner Core

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Physics Textbooks

Electric Charge Field and Potential

Medical Physics

Kinematics Physics

Famous Physicists

Torque and Rotational Motion

Work Energy and Power

Study anywhere. Anytime. Across all devices.