Science Olympiad Dynamic Planet Practice Test

What is the structure of the inner core primarily made of?

1. Ionic compounds

2. Liquid magma

3. Iron-nickel alloy

4. Sodium-potassium compounds

The correct answer is: Iron-nickel alloy

The inner core of the Earth is primarily made of an iron-nickel alloy. This conclusion is supported by seismic data that indicate how shock waves travel through the Earth, as well as experimental studies of materials under extreme pressure and temperature conditions similar to those found deep within the Earth. In the inner core, the immense pressure and high temperatures have resulted in the solidification of iron and nickel, which are the most abundant metals found in the Earth's composition. The dense arrangement of these metals creates a solid sphere that is roughly as hot as the surface of the sun, yet remains solid due to the extreme pressure. Understanding the composition of the inner core is crucial for comprehending geophysical processes such as the generation of Earth's magnetic field and the dynamics of plate tectonics. This core solids contribute to the overall structure and stability of the planet.