Final answer:
Earth's interior is structured into layers: the crust, mantle, outer core, and inner core. Seismic studies and computer modeling help scientists understand the composition and physical properties of these layers.
Step-by-step explanation:
The Earth's interior is composed of several distinct layers: the crust, the mantle, the outer core, and the inner core. At the center of our planet lies the inner core, a solid sphere made of iron and nickel alloy. This layer is extremely dense and under great pressure. Surrounding the inner core is the outer core, a sea of liquid iron and nickel believed to generate Earth's magnetic field.
Above the outer core is the mantle, which makes up the majority of Earth's volume. The mantle consists of solid material that can flow like plastic due to its semi-fluid state. The outermost layer is the crust, Earth's thin, solid shell that has two main types: continental and oceanic. Each differs in thickness and composition.
Scientists use seismic studies, which analyze the waves generated by earthquakes, and sophisticated computer modeling to understand these layers and the depths at which they are situated. By studying how these waves travel through Earth's interior, researchers can make inferences about the composition and state of these various layers.