Chapter 26, Problem 7RQ

What is the evidence that Earth’s inner core is solid?

To determine

The evidence that Earth’s inner core is solid.

Answer to Problem 7RQ

When they reach about depth of the Earth, S-waves do not cross over but P-waves travel further and lose its speed with refraction. This happens due to the change in density.

Explanation of Solution

P-waves are fastest in the solids and also, they can travel through solids, liquids, and gaseous materials.

P-waves are generated from the epicentre and travel through the core of the Earth’s surface. These waves are the fastest in the inner core and suddenly slow down when they reach the boundary of the inner and outer core. In the outer core, P-waves refracts due to the change in density of the rocks present in the outer core.

S-waves cannot travel through liquids and thus they can travel only in the inner core of the Earth’s core. This gives the evidence that the Earth’s inner core is solid.

The core is made up of iron and thus the inner core is the solid iron inner core and outer core is the molten iron outer core.

Conclusion:

Therefore, when they reach about depth of the Earth, S-waves do not cross over but P-waves travel further and lose its speed with refraction. This happens due to the change in density.