The outer core is primarily in which physical state?

The outer core is primarily in which physical state?

• A. Solid
• B. Gas
• C. Liquid
• D. Plasma

Answer: (C)

The main idea here is how temperature and pressure inside Earth determine whether a region is solid or liquid. In the outer core, temperatures are extremely high, hot enough to melt the iron–nickel alloy that makes up the core. Even though the pressure is immense, it doesn’t keep this layer solid; the conditions are such that the metal exists as a molten, flowing liquid. That liquid movement is crucial because it drives convection currents that generate Earth’s magnetic field. For comparison, the inner core stays solid because the pressure there is even higher, raising the melting point above the surrounding temperatures. So the outer core is a liquid.

The main idea here is how temperature and pressure inside Earth determine whether a region is solid or liquid. In the outer core, temperatures are extremely high, hot enough to melt the iron–nickel alloy that makes up the core. Even though the pressure is immense, it doesn’t keep this layer solid; the conditions are such that the metal exists as a molten, flowing liquid. That liquid movement is crucial because it drives convection currents that generate Earth’s magnetic field. For comparison, the inner core stays solid because the pressure there is even higher, raising the melting point above the surrounding temperatures. So the outer core is a liquid.