1-1 Physical Properties of Earth's Layers

Core

At the center of the Earth is a dense hot ball called the core. The inner core is solid metal made up of nickel and iron. It is surrounded by an outer core that is made of liquid molten nickel and iron.

Convection

Convection involves the cyclical movement of hot and cold materials. In Earth's asthenosphere, in the portion of the mantle that is right below the lithosphere, hot solid rock rises toward the surface as cooler rock sinks. This convection of fluid rock transfers energy from Earth's hot interior toward the cooler surface.

Tectonic Plate

Earth's crust is made up of many separate pieces known as tectonic plates. When two continental plates collide, they cause the crust to fold and form mountains like the Himalayas.

Geology

Geology is the study of Earth. An expert who studies geology is called a geologist.

Granite

Granite is an igneous rock that consists mainly of quartz, mica, and feldspar.

Heat

Heat is what happens when thermal energy is gained or lost.

Pressure

Pressure is the force exerted per unit area.

Radiation

Radiation is the transfer of energy through space in the form of electromagnetic waves. Earth's surface receives solar radiation from the Sun. Part of this energy is absorbed by the surface, while some is reflected back upwards. Greenhouse gases in the atmosphere absorb some of this radiation and redirect it back to Earth.

Asthenosphere

The asthenosphere is the soft and plastic layer in Earth's upper mantle, just below the lithosphere.

Mantle

The crispy fruit of an apple separates the outer skin from the seeds at the apple's center. The layer between the Earth's outside crust and its hot inner core is called the mantle. The mantle is mostly made of rock. Besides being the middle layer, it is also the largest layer of the earth.

Magma

The earth is made of rock. Inside the earth, it is so hot that some rocks melt. The melted rock is called magma. Pressure inside the Earth will push up magma through the opening of a volcano.

Lithosphere

The lithosphere is made up of the oceanic crust, the continental crust and the rocky outer layer of the mantle. It is approximately 60 miles deep. The lithosphere is broken into plates. Below the lithosphere, the mantle is semi-solid. The plates float on this and move a few centimeters every year.

Magnetic Field

The magnetic field around a magnet can be identified by using iron filings or a compass. A compass points northward because Earth itself is a giant magnet, surrounded by a magnetic field.

Volcano

Volcanoes form when lava, or liquid rock, erupts on Earth's surface. Volcanoes are characterized by a vent through which lava and pyroclastic material continue to erupt. There are a number of different types of volcanoes.

Density

What happens when you pour honey, water and oil into the same container? The honey always sinks to the bottom. Then, there is a layer of water in the middle. The oil layer is always on top. Even if you shake the container, each layer will settle again because of their densities. The mass of oil per unit volume is the least. The oil rises to the top. The density of honey is the greatest and it sinks to the bottom.