What is the composition of Earth's core?
A. very dense
B. Very liquid
C. mostly iron
D. mostly silicate material
The correct answer is C. mostly iron. The Earth's core is primarily composed of iron, with smaller amounts of nickel. It is divided into two parts: the inner core and the outer core. The inner core is solid and consists mainly of iron, while the outer core is liquid and also contains iron and nickel.
The composition of Earth's core can be described as mostly iron.
The composition of Earth's core is mostly iron, so the correct answer is C. Let me explain how scientists have come to this conclusion.
To determine the composition of Earth's core, scientists cannot directly access it because it lies deep beneath the Earth's surface. However, they have relied on multiple lines of evidence to infer its composition.
One way scientists study the core is through seismic waves, which are vibrations that travel through the Earth when there is an earthquake or explosion. By analyzing the behavior of these waves, scientists can map the interior structure of the Earth.
Seismic waves can be divided into two types: P-waves (primary waves) and S-waves (secondary waves). P-waves are compression waves that can travel through solids and fluids, while S-waves are shear waves that can only pass through solids.
When seismic waves pass through the Earth's core, they experience changes in their velocities and paths. These changes suggest that the core is composed of primarily liquid material. Therefore, the core cannot be entirely solid iron.
Additionally, scientists have studied meteorites, which are fragments of other celestial bodies that have fallen to Earth. Some meteorites contain iron-nickel alloys, which are similar in composition to the Earth's core. This further supports the idea that the core is composed mostly of iron.
Based on these lines of evidence and other experiments, scientists believe that Earth's core consists of an outer core, which is primarily liquid iron, and an inner core, which is a solid ball of iron-nickel alloy. Therefore, the most accurate answer to the question is C. mostly iron.