Final answer:
Iron and nickel are the two dense elements that sink to form Earth's core. The core's composition is inferred from Earth's density, rotation, and gravity studies, and it aligns with the composition found in metallic meteorites.
Step-by-step explanation:
The two dense/heavy elements that sink to the center of the Earth to create the core are iron and nickel.
Under the force of gravity, these heavier elements sank toward the inner parts of the planet when it was once in a hot, molten state, leading to the formation of Earth's dense metallic core.
The presence of a metallic core is inferred from various evidence, including the overall density of the planet and studies of Earth's gravity field.
Specifically, scientists know that Earth's core must be denser than its surface layers because of the calculated overall density of the planet based on its rotation.
This core is thought to be composed of about 85% iron and 15% nickel, with similar compositions seen in metallic meteorites, which are considered representative of core material.
Earth's core has a liquid outer layer and a solid innermost part, with the entire structure compressed to very high densities due to the weight of the overlying materials.