5.8  Earth’s surface is constantly changing. Key concepts include

1. Earth's internal energy causes movement of material within the Earth;
2. plate tectonics describe movement of the crust;
3. the rock cycle models the transformation of rocks;
4. processes such as weathering, erosion, and deposition change the surface of the Earth; and
5. fossils and geologic patterns provide evidence of Earth’s change.

5.9 The conservation of energy resources is important. Key ideas include

1. some sources of energy are considered renewable and others are not;
2. individuals and communities have means of conserving both energy and matter; and
3. advances in technology improve the ability to transfer and transform energy.

Central Idea: Earth’s geosystem is constantly changing; these changes are modeled in the rock cycle and through plate tectonics.

A system is a set of interrelated parts that make up a unified whole. The Earth system is composed of interrelated parts to include the atmosphere (air), geosphere (solid Earth), biosphere (organisms), and hydrosphere (water). Systems are seamlessly connected through the flow of matter and energy.

EARTH'S LAYERS

• Earth is constantly changing; these changes occur both on and beneath Earth's surface.
• Earth is composed of four concentric layers—the crust, mantle, outer core, and inner core—each with its own distinct characteristics.
  • The outer two layers are composed primarily of rocky material.
  • The innermost layers are composed mostly of iron and nickel.
• Pressure and temperature increase with depth beneath the surface.

PLATE MOVEMENT

• Earth's thermal energy causes movement of material within Earth.
  • Large continent-size plates move slowly about Earth's surface, driven by that thermal energy.
• Most earthquakes and volcanoes are located at the boundaries of the plates (faults).
• Plates can move
  • toward each other (convergent boundaries),
  • apart from each other (divergent boundaries), or
  • slip past each other horizontally (transform boundaries)


• Geological features in the oceans (including trenches and mid-ocean ridges) and on the continents (mountain ranges, including the Appalachian Mountains) are caused by current and past plate movements.
Mid-ocean Ridge Formation                 Appalachian Mountain Formation

ROCK CYCLE

• Rocks move and change due to heat and pressure within Earth and due to weathering, erosion, and deposition at the surface.
• These and other processes constantly change rock from one type to another.
• Depending on how rocks are formed, they are classified as
  • sedimentary (layers of sediment cemented together),
  • igneous (melted and cooled), and
  • metamorphic (changed by heat and pressure).

WEATHERING & EROSION

• Rocks and other materials on Earth's surface are constantly being broken down by both chemical and physical weathering.
  • The products of weathering include clay, sand, rock fragments, and soluble substances.
  • Materials can be moved by water and wind (erosion) and deposited in new locations as sediment (deposition).

ANCIENT EARTH - FOSSILS

• Fossils provide information about life and conditions in the past.
• Fossils may be found in different rock layers, which allows scientists to infer changes in landscapes.

Central Idea: Some resources are considered renewable and others are not. It is possible to conserve energy.

Energy cannot be created or destroyed; however, the availability of certain energy sources differs. Most of the energy used in the United States comes from non-renewable sources.

• Nonrenewable energy sources are natural resources that cannot be replaced after they are used because they take millions of years to form.
  • Fossil fuels such as petroleum, coal, and natural gas are all nonrenewable energy sources.

• Renewable energy sources come from resources that are replaced naturally and can be used again.
  • Wind energy, water behind dams, and sunlight are examples of renewable energy sources.
• Energy use affects the environment in many ways.
  • In general, fossil fuels do more harm to the environment than the use of renewable energy sources.
  • Some harmful consequences of energy use include air and water pollution and wildlife and habitat loss.
• There are many ways to conserve energy.
  • In the home, actions such as turning off the lights and electronic devices when not in use, taking shorter hot showers, and adjusting the thermostat by a few degrees (higher in summer, lower in winter) will conserve energy.
  • Walking or biking instead of taking the car for short trips also conserves energy.
• Advances in technology continually improve our ability to harness and use energy more efficiently.