... core is almost entirely composed of iron. Earth's magnetic field is believed to be controlled by the liquid outer core. The Earth is separated into layers based on mechanical properties in addition to composition. The topmost layer is the lithosphere, which is comprised of the crust and solid portion ... of the upper mantle. The lithosphere is divided into many plates that move in relation to each other due to tectonic forces. The lithosphere essentially floats atop a semi-liquid layer known as the ... to move around since the asthenosphere is much weaker than the lithosphere. Everythin...

• Word Count: 1504
• Approx Pages: 6
• Grade Level: High School