APES unit 4

• Plate Tectonics

  The study of the huge slabs of rock or lithosphere floating on top of a molten magma sea, the mantle
• Tectonic plates

  • Huge slabs of rock or lithosphere floating on top of a molten magma sea, the mantle
• Mantle

  A liquid layer of rock beneath the Earth's surface, due to the heat given off by the Earth's core
• Earth's core

  A dense ball of nickel-iron and radioactive elements that decay, giving off a tremendous amount of heat
• Types of plate boundaries

  • Divergent
  • Convergent
  • Transform
• Divergent boundary

  1. Plates move away from each other due to hot mantle material rising to the surface, pushing them apart

  2. Seafloor spreading: The creation of mid-oceanic features like trenches and underwater ridges
• Convergent boundary

  1. Plates collide, with one plate being subducted (forced) beneath the other due to density differences

  2. Subduction: The process of one plate being forced beneath another, often resulting in volcanic mountain ranges and trenches
• Transform boundary

  1. Plates slide past each other in opposite directions, often resulting in earthquakes

  2. Transform faults: Areas where two plates are sliding past each other, creating earthquakes when the force of the magma beneath them overcomes the friction between them
• Soil

  A complex mixture of tiny particles of weathered rocks, such as sand, silt, and clay, but it also has organic material, like living microbes or decomposers, and non-living organic material like decomposing leaves and animal waste
• Weathering

  The breakdown of rocks into smaller pieces due to the force of rain and the freeze-thaw cycle
• Parent material

  The original rocks that the soil particles came from
• Erosion

  The movement of weathered rock particles by wind and rain, which can lead to soil degradation
• Soil horizons

  • O Horizon: Organic matter, decomposers, plants roots, and partially decomposed biomass
  • A Horizon (Topsoil): Mix of organic matter and mineral components, containing nutrients like nitrogen and phosphorus
  • B Horizon (Subsoil): Little organic material, but still contains nutrients
  • C Horizon: Original parent material, with minimal weathering
• Soil texture

  • Sand: Large pores, easy water drainage
  • Silt: Medium-sized particles, with intermediate pores
  • Clay: Small pores, poor water drainage
• Soil pH

  A measure of acidity or basicity, with lower pH levels indicating acidity and higher pH levels indicating basicity
• Soil pH goes down (becomes more acidic)

  It can lead to lower nutrient levels and damage to plant roots
• Soil fertility

  The ability of the soil to support plant growth
• Factors affecting soil fertility

  • Nutrient levels (e.g. nitrogen and phosphorus)
  • pH levels
  • Other chemical and physical properties of the soil
• Composition of the atmosphere

  • Nitrogen (N2): 78%
  • Oxygen (O2): 21%
  • Argon (Ar): 1%
  • Trace gases: 0.4%, including greenhouse gases like methane and carbon dioxide
• Layers of the atmosphere

  • Troposphere: Weather occurs here, air closest to Earth
  • Stratosphere: Ozone (O3) layer, protects from UVB and UVC rays
  • Mesosphere: Gas molecules become less dense, middlemost layer
  • Thermosphere: Hottest layer, receives most direct solar radiation
  • Exosphere: Outermost layer, merges with outer space
• Temperature-altitude relationship in the atmosphere

  • Colder with increasing altitude in the troposphere
  • Warmer with increasing altitude in the stratosphere
  • Colder with increasing altitude in the mesosphere
  • Warmer with increasing altitude in the thermosphere
  • No specific temperature-altitude relationship in the exosphere
• Less densely packed gas molecules at each successive level of the atmosphere
• Opposite temperature-altitude relationship at each successive level of the atmosphere
• Warm air


  Holds more moisture than cold air
• Warm air rises

  Air cools and condenses as it rises, causing water vapor to condense
• Air moves


  From high pressure to low pressure
• Hadley Cell and global wind patterns

  1. Warm air rises at the equator, creating low pressure and rainy conditions

  2. Air cools and condenses, causing water vapor to condense and fall as rain

  3. Air begins to spread out and sink back down to Earth around 30° north and south, creating high pressure and dry conditions

  4. Air flows from high pressure to low pressure, creating global wind patterns
• Watershed

  An area of land that drains into one central body of water
• Characteristics of watersheds

  • Slope: affects the movement and quality of water in the watershed
  • Vegetation and soil type: affect the quality of water in the watershed
• Steeper slopes in a watershed

  Result in less chance for water to infiltrate the soil and more likely to runoff across the surface
• More vegetation and permeable soil in a watershed

  Result in better water filtration and quality
• Urban areas in a watershed

  Large areas of impermeable surfaces cause rainwater to runoff across the surface, leading to poor water quality
• Forests in a watershed

  Vegetation and permeable soil allow water to infiltrate and filter, resulting in better water quality
• Insolation

  The amount of the sun's rays or solar radiation that an area on Earth receives, measured in Watts per meter squared
• Factors affecting insolation

  • Curvature of Earth's surface: Areas close to the equator receive more direct radiation at a near perpendicular angle, concentrating solar energy on a smaller area, which increases insolation. Areas at higher latitudes receive less direct solar radiation due to the sun's rays striking at a more oblique angle, spreading the rays over a larger surface area.
  • Amount of atmosphere: The sun's rays pass through more atmosphere at higher latitudes, causing a lot of solar radiation to be scattered by gas molecules, reducing insolation.
• Earth's seasons

  Caused by the Earth's tilt (about 23.5° on its axis), not the Earth getting closer or further away from the Sun
• Seasons in detail

  • Summer: June 21st, tilted towards the Sun, longer day
  • Fall: September 21st-24th, parallel to the Sun, equal day length
  • Winter: December 21st, tilted away from the Sun, shorter day
  • Spring: March 20th-21st, parallel to the Sun, equal day length
• Tropic of Cancer

  23.5° north latitude, receives most direct insulation during the June Solstice
• Tropic of Capricorn

  23.5° south latitude, receives most direct insulation during the December Solstice
• Proximity to a large body of water

  Prevailing winds move across the body of water, picking up moisture, and then deposit it as precipitation when they reach land, leading to higher precipitation in areas near large bodies of water