What is the outer core primarily made of?

The outer core of the Earth is primarily composed of liquid iron and nickel. This part of the Earth's interior lies beneath the mantle and surrounds the inner core, which is solid. The high temperatures present in the outer core (estimated to be around 4,000 to 6,000 degrees Celsius) cause the iron and nickel to exist in a molten state, rather than solid. This fluid motion within the outer core plays a crucial role in generating Earth's magnetic field through the dynamo effect, where the movement of conductive fluids generates electric currents.

In contrast, the other options refer to materials that either make up different parts of the Earth's structure or are not found in the outer core. Solid rock and minerals primarily compose the Earth's crust and upper mantle, silicon and magnesium are common components of silicate minerals found in the mantle and crust, while diamonds and carbon are not relevant to the core's makeup. Understanding these distinctions is important for grasping the composition and behavior of the Earth's layers in geological contexts.