Which description best defines the Earth's outer core?

Which description best defines the Earth's outer core?

• A. A solid ball of iron and nickel at Earth's center
• B. A liquid layer of iron and nickel surrounding the inner core
• C. A rocky shell on the outside of the Earth
• D. A layer of crustal rocks above the mantle

Answer: (B)

The outer core is a liquid layer of iron and nickel that surrounds the solid inner core. This molten metal lies beneath the mantle and above the inner core, and its liquid state allows convection currents to flow. Those currents generate Earth’s magnetic field through the geodynamo process. This is distinct from the solid inner core at the center and the rocky crust and mantle above it. Seismic data also show that liquids don’t transmit S-waves, which helps confirm its liquid nature.

The outer core is a liquid layer of iron and nickel that surrounds the solid inner core. This molten metal lies beneath the mantle and above the inner core, and its liquid state allows convection currents to flow. Those currents generate Earth’s magnetic field through the geodynamo process. This is distinct from the solid inner core at the center and the rocky crust and mantle above it. Seismic data also show that liquids don’t transmit S-waves, which helps confirm its liquid nature.