Grade 7 Ch 5 L 2: Earth's Interior

The crust is the outermost layer of the Earth and is the thinnest compared to the mantle and core. It is composed of solid rocks and is divided into two types: continental crust and oceanic crust. The continental crust is thicker and less dense than the oceanic crust. The crust is where we live and where most geological activity occurs, such as earthquakes and volcanic eruptions.

Scientists have discovered that the Earth's core is made up of two parts by studying earthquake waves. This suggests that the core consists of an outer core and an inner core. The outer core is believed to be composed of liquid iron and nickel, while the inner core is thought to be solid. This information has been gathered through the analysis of seismic waves and their behavior as they pass through different layers of the Earth. Therefore, the statement "True" is the correct answer.

The lithosphere is the correct answer because it is the layer of the Earth that includes the crust and upper mantle. The crust is the outermost layer of the Earth, and the uppermost part of the mantle is also included in the lithosphere. This layer is rigid and is broken into several tectonic plates that float on the semi-fluid asthenosphere below. The lithosphere plays a crucial role in plate tectonics and is where most geological activity occurs, such as earthquakes and volcanic eruptions.

The asthenosphere is the layer of the Earth that flows like soft plastic. It is located beneath the lithosphere and is made up of partially molten rock. This layer is responsible for the movement of tectonic plates and is able to flow due to the high temperature and pressure. The asthenosphere plays a crucial role in the process of plate tectonics and the formation of mountains, earthquakes, and volcanic activity.

The inner core of the Earth is made up of iron crystals. This layer is located at the very center of the Earth and is believed to be solid due to the immense pressure it experiences. The high temperatures and pressure in the inner core cause the iron to crystallize, forming a solid mass.

The mantle is the layer of the Earth that lies between the crust and the core. It is composed of solid rock and is the thickest layer, extending approximately 2,900 kilometers below the Earth's surface. The mantle is responsible for the movement of tectonic plates and plays a crucial role in the Earth's geological processes.

The statement "Temperate and pressure decrease with depth" is false. In general, as depth increases, temperature tends to decrease due to the absence of sunlight and the cooling effect of the surrounding environment. However, pressure increases with depth due to the weight of the overlying water or atmosphere. Therefore, the correct answer is false.

The outer core of the Earth is made of liquid metal. This layer is located between the mantle and the inner core. It consists mainly of molten iron and nickel, and it is the only liquid layer in the Earth's interior. The high temperatures and pressures in the outer core keep the metal in a liquid state, allowing it to flow and generate the Earth's magnetic field through a process called the dynamo effect.

The MAGNETOSPHERE protects the Earth from the Sun's dangerous cosmic rays.

Compass needles point N because of the Earth's magnetic FIELD.