Units
- Unit Overview
- Unit A: The Solid Earth
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: A Walk on the Bottom of the Sea
  - Unit Lessons
  - A1: Earth as a System
    - - Guiding Question: What makes up the Earth system?
    - - Key Concepts
      - The Earth is a dynamic planet made up of five interrelated natural systems.
      - These natural systems consist primarily of air (atmosphere), water (hydrosphere), ice and snow (cryosphere), all living organisms (biosphere), and rocks (geosphere).
  - A2: Earth's Layered Structure
    - - Guiding Question: What characterizes the interior of the Earth?
    - - Key Concepts
      - The Earth is composed of several distinct layers, each with its own specific characteristics.
      - The interior of the Earth is heated primarily by radioactive decay.
  - A3: Oceans and Continents
    - - Guiding Question: How do we distinguish between the different types of crust?
    - - Key Concepts
      - Oceanic and continental crusts are primarily defined by differences in chemical composition and in density.
      - Continents and oceans each have a number of distinguishing physical features.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Unit B: Plate Tectonics
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: Antarctica’s Warmer, Not Gentler Past
  - Unit Lessons
  - B1: Continental Drift
    - - Guiding Question: What evidence supports the idea that continents are in motion?
    - - Key Concepts
      - The shape and position of today’s continents is the result of movement over time of landmasses that were originally part of a giant supercontinent.
      - The shapes of continents, as well as geologic, fossil, and climate evidence all provide clues that continents have moved over time.
  - B2: Seafloor Spreading and Paleomagnetism
    - - Guiding Question: Why is ocean crust so much younger than continental crust?
    - - Key Concepts
      - The theory of seafloor spreading states that new ocean crust is continually being formed, and that this crust is slowly carried away from its point of origin over a period of time.
      - The study of the repeated reversal of the Earth’s magnetic poles over time has provided convincing evidence of seafloor spreading.
  - B3: The Theory of Plate Tectonics
    - - Guiding Question: Why has the theory of plate tectonics been so successful as an explanation for the movement of continents?
    - - Key Concepts
      - The lithosphere is broken into plates that are constantly in motion.
      - Interacting plate boundaries are distinguished by three different types of plate interactions.
      - Convection is the fundamental underlying mechanism driving plate motion.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Unit C: Minerals and Rocks
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: The Fascination of Marble
  - Unit Lessons
  - C1: Minerals - Building Blocks of Rocks
    - - Guiding Question: What is the difference between a mineral and a rock?
    - - Key Concepts
      - A mineral is a solid with specific characteristics that define a unique composition and structure.
      - Rock is composed of a combination of different minerals.
  - C2: The Rock Cycle
    - - Guiding Questions: What is the rock cycle? How does the rock cycle work?
    - - Key Concepts
      - The three main types of rocks, based on how they are formed, are igneous, sedimentary, and metamorphic.
      - Rocks are continuously forming, changing, and reforming through the rock cycle.
  - C3: Igneous, Sedimentary and Metamorphic Rocks
    - - Guiding Question: What are the processes that produce the different types of rock?
    - - Key Concepts
      - The process by which a rock is formed influences its characteristics.
      - The environment in which the process takes place also influences a rock’s characteristics.
  - C4: Weathering and Soil Formation
    - - Guiding Question: What processes produce soil?
    - - Key Concepts
      - Physical and chemical processes break down rocks over time.
      - Soil formation is influenced by the interaction of geological, biological, and meteorological processes.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Unit D: Shaping The Earth
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: Living Through the Dust Bowl
  - Unit Lessons
  - D1: Shaping Earth’s Surface
    - - Guiding Question: What processes are involved in shaping Earth's many different landforms?
    - - Key Concepts
      - Internal and external processes modify the Earth’s surface.
      - Erosion is one of the major processes that shape the Earth’s landforms.
  - D2: Mass Movement
    - - Guiding Question: What role does gravity play in shaping Earth's surface?
    - - Key Concepts
      - Mass movement is the movement of rock and soil down an incline by the force of gravity.
      - Mass movement can create a variety of natural features and landforms.
  - D3: Water and Ice Landforms
    - - Guiding Question: What role does water and moving ice play in shaping Earth's surface?
    - - Key Concepts
      - Water is the Earth’s most important agent of erosion and is responsible for shaping a variety of landforms.
      - Glaciers produce unique landforms directly through erosion, and by the deposition of material.
  - D4: Wind Landforms
    - - Guiding Question: What role does wind play in shaping Earth's surface?
    - - Key Concepts
      - Wind is an active agent of erosion.
      - Deposition of windblown sediment produces significant landforms.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Unit E: Earthquakes
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: Mark Twain's First Earthquake
  - Unit Lessons
  - E1: Earthquakes and Faults
    - - Guiding Question: What is an earthquake?
    - - Key Concepts
      - Earthquakes are caused by the interaction of Earth's plates.
      - The sudden release of stored energy, in the form of movement along a fault, produces an earthquake.
  - E2: Earthquakes and Waves
    - - Guiding Question: How is energy transmitted during an earthquake?
    - - Key Concepts
      - Earthquake waves that travel through the Earth's interior are subdivided into primary (P) and secondary (S) waves.
      - Earthquake surface waves travel through the Earth’s outer layer.
  - E3: The Strength of Earthquakes
    - - Guiding Question: How do we determine the location and strength of an earthquake?
    - - Key Concepts
      - The different arrival time of earthquake waves can be used to pinpoint the location of an earthquake.
      - The strength of an earthquake can be determined either by the intensity of the earthquake or by the size of the seismic waves.
  - E4: Seismic Waves and the Earth's Interior
    - - Guiding Question: How can seismic waves be used to help determine the composition of the Earth’s interior?
    - - Key Concepts
      - The different arrival time of P waves can be used to determine the location of the crust-mantle boundary.
      - Evidence of a liquid core comes from the existence of shadow zones for P and S waves.
  - E5: Living with Earthquakes
    - - Guiding Question: What is the impact of earthquakes on society?
    - - Key Concept
      - Earthquakes have major social and economic consequences.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Unit F: Volcanoes
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: A Journey to the Center of the Earth
  - Unit Lessons
  - F1: Formation of Volcanoes
    - - Guiding Question: How are volcanoes formed?
    - - Key Concepts
      - Most volcanoes occur along tectonic plate boundaries.
      - Volcanoes can occur far from plate boundaries as a result of stationary plumes of molten rock called "hot spots."
  - F2: Types of Volcanoes
    - - Guiding Question: How do we classify volcanoes?
    - - Key Concepts
      - The force of a volcanic eruption is related to its lava type.
      - The shape of a volcano is determined by the chemical composition of the magma.
  - F3: Living with Volcanoes
    - - Guiding Question: What are the major social and economic effects of volcanic eruptions?
    - - Key Concepts
      - Volcanic eruptions have both positive and negative effects on society.
      - Scientists have had some success at predicting the general likelihood of an eruption.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Unit G: Geologic Time
  - Get Ready
  - Unit Overview and Big Ideas
  - What Do You Already Know?
  - Literacy Link: There Was a Second Sun
  - Unit Lessons
  - G1: Age of the Earth
    - - Guiding Question: What methods are used to learn about the long history of the Earth?
    - - Key Concepts
      - Relative ages of rocks can be determined by comparing rock layers.
      - The absolute ages of rocks can be determined through radioactive decay.
      - Fossils provide evidence of the Earth’s past.
  - G2: The Geologic Timescale
    - - Guiding Question: How have the Earth’s life-forms and landmasses changed over time?
    - - Key Concepts
      - Geologic time is broken down into smaller units called eras.
      - These eras correspond to major changes in the Earth’s life-forms.
      - These eras also correspond to major changes in form and position of the Earth’s landmasses.
  - G3: Catastrophic Events and Mass Extinction
    - - Guiding Question: How have catastrophic events affected life on the Earth?
    - - Key Concepts
      - A catastrophic event is a short timescale event that has long-term effects on life and the environment.
      - Catastrophic events have been responsible for a number of large mass extinctions in Earth’s history.
  - G4: Earth’s Future
    - - Guiding Question: What does the future hold for the Earth?
    - - Key Concepts
      - Tectonic plates will continue to move, possibly resulting in the emergence of a new supercontinent 250 million years in the future.
      - The death of the Earth is expected to occur in about 5 billion years as a result of the sun becoming a red giant.
  - Wrap Up
  - What Do You Know Now?
  - Unit Activity
- Glossary
Teachable Moments
- Lessons
- 2011 Japan Earthquake and Tsunami
  - - Guiding Question: What were the causes and effects of the March 11, 2011 earthquake in Japan?
  - - Key Concepts
    - Earthquakes are caused by the interaction of Earth's tectonic plates.
    - Earthquakes can generate a tsunami.
    - Earthquakes have major social and economic consequences.
- 2015 Gorkha (Nepal) Earthquake
  - - Guiding Question: What were the causes and effects of the massive earthquake that occurred in Nepal on April 25, 2015?
  - - Key Concepts
    - Earthquakes are caused by the interaction of Earth’s tectonic plates.
    - Nepal is tectonically active because of a convergent boundary between the Indian Plate and the Eurasian Plate.
    - Earthquakes have major social and economic consequences.
- 2016 Ecuador Earthquake
  - - Guiding Question: What were the causes and effects of the massive earthquake that occurred in Ecuador on April 16, 2016?
  - - Key Concepts
    - Earthquakes are caused by the interaction of Earth’s tectonic plates.
    - Ecuador is tectonically active because of a convergent boundary between the Nazca Plate and the South American Plate.
    - Earthquakes have major social and economic consequences.
- 2018 Honduras Earthquake
  - - Guiding Question: What were the causes and effects of the earthquake that occurred in Honduras on January 9, 2018?
  - - Key Concepts
    - Earthquakes are caused by the interaction of Earth’s tectonic plates.
    - Honduras is tectonically active because of the four plates that form the perimeter of the Caribbean plate.
    - Earthquakes have major social and economic consequences.
  - - 1: Earthquake In Honduras
    - 2: Plate Boundaries
- 2018 Gulf Of Alaska Earthquake
  - - Guiding Question: What were the causes and effects of the earthquake that occurred in the Gulf of Alaska on January 23, 2018?
  - - Key Concepts
    - Earthquakes are caused by the interaction of Earth’s tectonic plates.
    - The Aleutian Arc is a tectonically active area.
    - Earthquakes have major social and economic consequences.
  - - 1: Gulf Of Alaska Earthquake
    - 2: Historical Precedent
- 2023 Turkey-Syria Earthquake
  - - Guiding Question: What were the causes and effects of the massive earthquake(s) that occurred in Turkey on February 6, 2023?
  - - Key Concepts
    - Earthquakes are caused by the interaction of Earth’s tectonic plates.
    - Turkey is tectonically active because of the interactions between three tectonic plates, the Anatolian Plate, the Arabian Plate, and the African Plate.
    - Earthquakes have major social and economic consequences.