EARTH SCIENCE

• p-waves can move through solid, liquid, and gas.
• P-waves exert compressional force.
• S-waves = shear waves
• S-waves can only travel through solid.
• Shear waves have a wavelength that is a fraction of the wavelength of the longitudinal waves
• Earth's original crust has been subjected to extensive erosion.
• Eclipse shadows:

  Umbra is the darker, inner shadow.

  Penumbra is the lighter, outer shadow.
• Dissolution causes the formation of caves in limestone rocks
• Igneous rocks are composed of silicate materials: silicon and oxygen
• The aphelion refers to the point in a planet's orbit where it is farthest from the sun. In contrast, the perihelion is the point in a planet's orbit where it is closest to the sun.
• Streak (a physical characteristic of minerals) refers to the color left when a mineral is rubbed on a white surface.
• Due to sunlight's radiation pressure, comet tails always point away from the sun
• Water availability and quality can be affected by global warming and soil erosion
• Water covers 71% of Earth's surface
• Only 2.5% of water on Earth is freshwater
• Physical Characteristics of Minerals

  1. External Crystal Form
  2. Cleavage
  3. Fracture
  4. Lustre
  5. Color
  6. Streak
  7. Transparency
  8. Structure
  9. Hardness
  10. Density
  11. Tenacity
  12. Magnetism
  13. Reaction to acid
  14. Taste
  15. Smell
  16. Fluorescence
  17. Radioactivity
• The external crystal form is determined by internal molecular structure and the environment in which the crystal forms
• Mineral structure refers to its shape and size
• Cleavage refers to cracks in planar areas due to weak internal structure
• Fracture refers to cracks in non-planar areas due to weak internal structure
• Lustre of a mineral refers to the degree of shine
• The color of a mineral depends on the wavelengths the mineral absorbs and reflects
• The streak of a mineral is the color of a mineral when it is powdered or scratched against a surface
• The specific gravity or density of a mineral is measured by dividing the weight of a mineral by its weight of equal volume of water
• The weight of equal volume of water of a mineral is measured by getting the difference of the weight of the mineral in air and the weight of the mineral in water
• Mineral fluorescence is observed with UV light
• Some minerals are radioactive and emit radiation
• Low-pressure areas attract winds
• The Coriolis effect explains why storms rotate clockwise in the southern hemisphere and counter-clockwise in the northern hemisphere