Groundwater and Tectonic Plates Overview

Groundwater

• Groundwater is water that seeps into the Earth's crust through rock and sediment.
• It is always moving, never static.
• Three factors drive groundwater flow:
  • Porosity: The amount of water soil can hold.
  • Permeability: How quickly water passes through the earth. Clay has high porosity but low permeability.
  • Gravity: Pulls water downhill from higher to lower hydraulic gradients.

Tectonic Plates and Coastlines

• Earth's surface is made of tectonic plates (continental or oceanic).
• Plate movement causes tectonic activity, shaping land and sea.
• Active continental margins (where plates meet):
  • High tectonic and seismic activity.
  • Subduction occurs.
  • Features: mountain ranges, oceanic trenches, volcanic activity.
• Passive continental margins:
  • Low tectonic activity.
  • Flat inland areas.
  • Long rivers, estuaries.
• Coastlines:
  • Emergent (active margins): Steep, rocky cliffs.
  • Submergent (passive margins): Wide river valleys, drowned.

The Water Cycle

• The water cycle circulates water between various parts of Earth (streams, rivers, lakes, underground, seas, clouds).
• Evaporation, condensation, and precipitation are key.
• Water changes phases (solid, liquid, gas).
• Transpiration: Evaporation from plant leaves.
• Sublimation: Ice changing to vapor.
• Runoff: Water flowing across land.
• Infiltration: Water seeping into the ground.
• Energy from the sun drives the cycle, changing between kinetic and potential energy.
• The cycle is a continuous matter transfer and energy transfer.

Water Cycle Processes

• The water cycle recycles freshwater.
• Key processes:
  • Evaporation: Liquid to gas
  • Condensation: Gas to liquid
  • Precipitation: Water falling as rain, snow, etc.
  • Sublimation: Solid to gas
  • Transpiration: Evaporation from plants' leaves
  • Runoff: Water flowing over land
  • Infiltration: Water soaking into the ground

Water Molecules

• Molecules are made of bonded atoms.
• Water (H₂O): oxygen bonded to two hydrogen atoms via polar covalent bonds.
• Bent shape due to electron placement.
• Polar molecules have partial charges (dipoles) due to uneven electron distribution.
• In water: oxygen has a negative dipole, hydrogens have positive dipoles.
• Hydrogen bonding: Strong dipoles allow water to interact with other water molecules.
• Water's polarity: Only other polar molecules dissolve in water (hydrophilic).