How do we know that the Earth has layers, and how do we know what elements make up each of the layers?

Question

How do we know that the Earth has layers, and how do we know what elements make up each of the layers?

In: 10

Answer 1

Earthquake observatories are a thing that study the Earth just like astronomical observatories study the sky. Here is an example that uses a steel ball to create artificial earthquakes. https://youtu.be/vxfJbW6KDp4