Chapter 1: Introducing Earth Lesson 1: Review of Earth’s System Earth’s Structure Chapter 1: Introducing Earth Lesson 1: Review of Earth’s System

The Earth System System: a group of parts that work together as a whole. Energy allows Earth to work as a system as it moves matter through its parts.

The Atmosphere The relatively thin envelope of gases that forms Earth’s outermost layer. Mostly made of nitrogen and oxygen.

The Geosphere The geographic makeup of the Earth. Three main parts: a metal core, a solid middle layer, and a rocky outer layer.

The Hydrosphere Contains all of Earth’s water. About ¾ of Earth’s surface is covered, but more water can be found underground and in different parts of the water cycle.

The Biosphere The parts of Earth that contain living organisms.

Constructive Forces Forces that construct, or built up, mountains are constructive forces. This often happens from the collision of two tectonic plates – sections of Earth’s lithosphere that move slowly over Earth.

Destructive Forces Destructive forces destroy and wear away landmasses through processes such as erosion and weathering. Remember: weathering is the breaking down of particles, erosion is them being carried away.

Chapter 1: Introducing Earth Lesson 2: Earth’s Interior Earth’s Structure Chapter 1: Introducing Earth Lesson 2: Earth’s Interior

Earth’s Interior Scientists gather information about Earth’s interior in two main ways: Rock samples: geologists have drilled up rock samples from 12.3 km into Earth. Seismic waves: geologists record waves after an Earthquake and measure the speed and paths taken by the waves to indicate how materials change inside Earth.

Earth’s Interior

Earth’s Layers There are three main layers of the Earth – the crust, the mantle, and the core. The deeper you go into Earth, the more pressure there is and the greater the temperature is. Pressure: the result from a force pressing on an area.

The Crust Crust: the layer of rock that forms Earth’s outer skin; layer of solid rock on land and on the ocean floor. Mainly made of two elements: oxygen and silicon. Usually between 5-40 km thick; thickest below mountains and thinnest at the ocean floor.

The Crust Crust beneath the ocean is called oceanic crust. Mostly composed of basalt, a dark, fine-grained rock. Crust that forms the continents is called continental crust. Made of many types of rocks, but most like granite, a rock that is light in color with coarse grains.

The Mantle The mantle is made of up rock that is very hot, but solid, and contains more magnesium and iron than the crust. About 3,000 km thick. Broken into 3 layers.

The Mantle Lithosphere - Asthenosphere – The crust and uppermost mantle; strong, hard, rigid rock. Asthenosphere – Solid, but can bend slightly; due to increased heat and pressure it is less rigid. Mesosphere (transition zone) – Lowest layer; becomes more rigid again

The Core Mostly made of iron and nickel. Liquid outer core 2,258 km thick Molten metal Solid inner core 1,222 km thick Very dense

The Layers of the Earth

The Magnetic Field Movement in the outer core has created the magnetic field, causing the planet to act like a magnet. The Earth’s magnetic north pole is not the same location at the Earth’s geographic North pole.

The Magnetic Field

Chapter 1: Introducing Earth Lesson 3: Convection and the Mantle Earth’s Structure Chapter 1: Introducing Earth Lesson 3: Convection and the Mantle

Transferring Heat When an object is heated, the particles move more quickly because they have more energy. Heat is transferred in three main ways: Conduction: direct contact between two objects Radiation: the transfer of heat through electromagnetic waves Convection: the transfer of heat through the mixing of liquids/gases

Transferring Heat

Convection in the Mantle Convection is caused by changes in density: a measure of how much mass there is in a given volume of a substance. Less dense materials rise to the top, while more dense materials sink to the bottom. Over time, these materials heat and cool to keep rising and sinking.

Convection in the Mantle A convection current is caused by the heating and cool, change in density, and force of gravity moving liquids and gases. Heat from the core heats the materials in the mantle, creating a convection current.