EarthSci

• Accretion


  Action where gravity attracts tiny bits of matter towards an object, resulting in a gradual increase in the object's size
• Homogeneous accretion hypothesis


  1. Formation of Earth began after condensation of particles of the primitive nebula

  2. Particles accreted to form a homogeneous primordial Earth

  3. Early Earth had a uniform solid composition

  4. Denser materials like iron and nickel sank towards the center

  5. Less dense silicates moved upwards

  6. Iron and nickel accumulated to form Earth's core

  7. A thin layer of solid rock formed the crust
• Heterogeneous accretion hypothesis


  1. Earth formed at the same time as its basic internal structure

  2. Particles condensed depending on their condensation points

  3. Denser particles like iron and nickel accreted first

  4. Silicates and volatile particles formed the outer layer
• Hydrosphere


  All water on Earth, including liquid water, water vapor, and ice
• Components of the hydrosphere

  • Oceans
  • Lakes
  • Rivers
  • Marshes
  • Clouds
  • Glaciers
  • Polar caps
• Saltwater


  Water that contains salt, found in oceans and seas
• Freshwater


  Water that contains small amounts of salt, found in rain, streams, ponds, lakes, and permanently frozen areas (permafrost)
• Water


  • Density is highest at 3.99°C and lowest at freezing temperature
  • Allows flow and transfer of substances from the cell to its environment and vice versa
  • Has high heat capacity, making it an excellent coolant
• The prevailing hypothesis on the origin of water on Earth is that it came from comets that collided with Earth
• Albedo


  The ability of a material to reflect light
• Black surfaces have low albedo and absorb more sunlight, while light-colored surfaces have high albedo and reflect more light
• Solar energy


  • Warms the Earth
  • Drives weather and climate
  • Can be harnessed through solar panels
• Earth's albedo is 30%, meaning 30% of the solar energy reaching Earth is reflected back into space
• The remaining 70% of solar energy is absorbed by the atmosphere, land, and oceans
• Factors affecting Earth's energy budget

  • Changes in the amount of radiation received from the Sun
  • Changes in Earth's orbit and tilt
  • Presence of greenhouse gases in the atmosphere
• Layers of the atmosphere

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere
• Hydrologic cycle


  The continuous movement of water on, above, and below the Earth's surface
• Processes in the hydrologic cycle

  • Evaporation
  • Condensation
  • Precipitation
  • Runoff
• Earth's subsystems


  • Atmosphere
  • Hydrosphere
  • Geosphere
  • Biosphere
• The atmosphere is composed primarily of nitrogen (75.1%), oxygen (20.9%), and argon (0.9%)
• Layers of the Earth

  • Crust
  • Mantle
  • Outer core
  • Inner core
• Mohorovičić discontinuity


  The boundary between the Earth's crust and mantle
• Biosphere


  All living things and their interactions with the physical environment
• Climate system


  The functioning of the atmosphere, hydrosphere, biosphere, and geosphere over a long period of time
• Greenhouse gases like carbon dioxide trap heat in the atmosphere, increasing Earth's surface temperature
• Mineral


  A naturally occurring inorganic homogeneous solid with a definite chemical composition and an ordered crystalline structure
• Minerals


  • Have distinctive characteristics like color, hardness, and crystal structure
• Vapor is the primary greenhouse gas
• The atmosphere undergoes different phases such as evaporation, condensation, and sublimation
• The transitions between these phases result in continuous absorption and emission of energy in the atmosphere
• Landforms affect the climate by acting as physical barriers for clouds and storms and when water is stored in the atmosphere and affects the amount of radiation from the sun
• Photosynthesis affects the climate system by absorbing carbon dioxide and providing oxygen
• Mineral


  A naturally occurring inorganic homogeneous solid with a definite chemical composition in an ordered crystalline structure, most minerals have distinctive characteristics
• Mineral


  • Color - refers to certain wavelengths of light that are reflected by the material, a property of a mineral and is often the first thing that people consider when looking for minerals as gemstones for jewelry
  • Luster - the appearance of a mineral surface and is independent on how it reflects light
• Types of luster


  • Pearly
  • Silky
  • Dull
  • Resinous
  • Earthy
  • Adamantine
  • Vitreous/glassy
  • Metallic
• Crystal habit


  • The characteristic shape in which a mineral grows and is a projection of the mineral's crystal structure
• Types of crystal habit

  • Acicular
  • Blocky
  • Tabular
  • Fibrous
  • Bladed
  • Dendritic
  • Prismatic
• Streak


  The color of the powder form of a mineral, observed by rubbing the mineral across a straight plate
• Cleavage


  The tendency of some minerals to break along flat surfaces, these surfaces have the weakest atomic bonding
• Types of cleavage


  • Basal
  • Prismatic
  • Non prismatic
  • Cubic
  • Rhombohedral
  • Octahedral
  • Sphalerite