APES UNIT 4 FINAL

Earth’s Structure

• Core:
  The dense, hot metal layer (mostly iron) at the center of the Earth. It generates the Earth’s magnetic field.

• Mantle:
  The hot, pliable, and less dense layer surrounding the core. Convection currents occur here, driving tectonic plate movement.

• Crust:
  The cool, brittle, outermost layer of Earth that floats on the mantle.

• Lithosphere:
  The rigid outer layer of Earth, including the crust and the upper mantle.

Tectonic Plates and Boundaries

• Tectonic Plate Movement:
  Driven by convection currents in the mantle.

• Convergent Boundaries:
  Where plates collide, forming mountains, island arcs, volcanoes, earthquakes, and subduction zones.

• Divergent Boundaries:
  Where plates move apart, forming rift valleys, seafloor spreading zones, volcanoes, and earthquakes.

• Transform Boundaries:
  Where plates slide past each other, causing earthquakes and creating faults (e.g., San Andreas Fault).

• Seafloor Spreading:
  The process by which new oceanic crust forms as magma rises at divergent boundaries.

Earthquakes

• Cause of Earthquakes:
  Sudden release of energy along faults or tectonic plate boundaries.

• Creep:
  Gradual movement along a fault.

• Epicenter:
  The surface location directly above the point where an earthquake originates.

Rock Cycle

• Igneous Rocks:
  Formed from cooled magma or lava.

• Sedimentary Rocks:
  Formed by compaction and cementation of sediments.

• Metamorphic Rocks:
  Formed by heat and pressure altering existing rocks.

• Weathering:

  • Mechanical Weathering: Physical breakdown of rocks (e.g., freezing and thawing).

  • Chemical Weathering: Alteration of rock composition (e.g., acid rain).

Soil

• Factors Influencing Soil Formation:
  Parent material, climate, organisms, topography, and time.

• Soil Particles:

  • Sand (largest).

  • Silt.

  • Clay (smallest).

  • Classified using a soil triangle.

Atmosphere

• Atmospheric Layers:

  • Troposphere: Contains most of the atmosphere’s mass; site of weather and convection currents.

  • Stratosphere: Contains the ozone layer that absorbs UV radiation.

  • Mesosphere: The coldest layer of the atmosphere.

  • Thermosphere: High temperatures and ionized gases; site of auroras.

Weather Patterns and Atmospheric Movement

• Coriolis Effect:
  The apparent deflection of moving air and water due to Earth’s rotation:

  • Deflects to the right in the Northern Hemisphere.

  • Deflects to the left in the Southern Hemisphere.
    Influences large-scale wind patterns (e.g., trade winds, westerlies) and ocean currents, creating curved movements.

• Jet Stream:
  A high-altitude, fast-moving air current in the upper troposphere:

  • Location: Forms between large air masses of different temperatures (polar and tropical).

  • Speed: Typically 110-250 mph.

  • Effects:

    • Steers storm systems and influences precipitation.

    • Regulates temperature by separating polar and tropical air masses.

    • Creates extreme weather when it dips (cold snaps) or rises (heatwaves).

  • El Niño Impacts: During El Niño, the northern Jet Stream shifts southward, causing wetter conditions in the southern United States. The southern Jet Stream strengthens, bringing intense storms.

• Convection Currents:
  Warm air rises near the equator, cools, and sinks, forming Hadley cells. Similar patterns in Ferrel and Polar cells drive global wind systems and influence tropical, temperate, and polar climates.

El Niño, La Niña, and ENSO

• El Niño:
  A warming phase of the Pacific Ocean that occurs every 3-7 years, disrupting weather patterns:

  • Impacts:

    • Wetter, stormier conditions in the Americas.

    • Drier, drought-prone conditions in Asia and Australia.

    • Warmer global temperatures due to heat released from oceans.

• La Niña:
  A cooling phase of the Pacific Ocean that intensifies normal circulation, causing:

  • Wetter conditions in Asia.

  • Drier conditions in the Americas.

• ENSO Cycle:
  A periodic shift in Pacific Ocean temperatures and atmospheric conditions that influences global weather systems.

Solar Radiation and Greenhouse Effect

• Seasons:
  Caused by the tilt of Earth’s axis and its orbit around the sun.

• Greenhouse Effect:
  Greenhouse gases (e.g., CO₂, methane) trap heat in the atmosphere, maintaining Earth’s temperature balance and preventing extreme fluctuations.

Weather Fronts

• Cold Fronts:
  Cooler air pushes warmer air upward, triggering strong storms.

• Warm Fronts:
  Warm air slides over cooler air, causing steady drizzle.

Hurricanes, Tornadoes, and Extreme Weather

• Conditions for Formation:
  Warm, moist air intensifies convection currents, forming spiraling systems:

  • Hurricanes: Over water.

  • Tornadoes: Over land.

• Latent Heat:
  Released during condensation, it intensifies convection and draws more warm air and moisture into storms.