Final answer:
The Earth's core consists of an inner core, which is solid and made mainly of iron and nickel, and an outer core, which is liquid and responsible for the Earth's magnetic field.
Step-by-step explanation:
The Earth's core is made of two main parts: the inner core and the outer core. The inner core is solid and composed primarily of an iron and nickel alloy. Surrounding the inner core is the outer core, which is a liquid layer also made of iron and nickel. This liquid outer core is crucial for the generation of the Earth's magnetic field. Outside of the core is the mantle, which is a thick layer of solid rock that behaves plastically due to high temperatures. Beyond the mantle lies the Earth's crust, which is the thin, outermost layer.
Deep insights into the core's composition come from seismic studies, the planet's gravitational pull and density, as well as from the study of meteorites. The density and magnetic properties of the Earth provide evidence that the core must be metallic, with iron being the predominant element, accompanied by nickel, and perhaps some amount of sulfur. The core's immense pressure and temperature conditions define its unique solid and liquid states.