Earth's Spheres and Hydrosphere Overview

Earth's Spheres

• Earth's surface divided into four interconnected spheres: Lithosphere, Hydrosphere, Atmosphere, and Biosphere.

Hydrosphere

• Derived from Greek “hydro” (water) and “sphaira” (sphere), covers water on, under, and above Earth's surface.
• Water Cycle:
  • Evaporation: Water changes to gas and enters the atmosphere.
  • Condensation: Gas cools and forms clouds.
  • Precipitation: Water falls back to Earth as rain, snow, or hail.
  • Transportation: Movement of water back to oceans and seas.
• Types of Water:
  • Saltwater: 97% of Earth's water, found in oceans and seas.
  • Freshwater: 3% available on continents and islands (rivers, lakes, groundwater).

Water Distribution

• Freshwater scarcity: most is trapped in ice and glaciers.
• Recycling water is crucial for sustainability and human consumption.
• Floods: Excessive water inundating normally dry land.
• Droughts: Extended periods of low rainfall impacting growth and living conditions.

Atmosphere

• Composed of 78% nitrogen, 21% oxygen, 1% carbon dioxide, argon, and water vapor.
• Variable Components: Aerosols, water vapor, and ozone.

Layers of the Atmosphere

• Exosphere: Outer layer, contains low densities of hydrogen and heavier molecules.
• Thermosphere: Home to auroras (northern and southern lights) and satellites, known for the ionosphere.
• Mesosphere: Area where meteors burn upon entry, creating bright streaks.
• Stratosphere: Houses the ozone layer; jet planes fly here.
• Troposphere: Closest layer to Earth, where weather changes occur and humans live.

Ozone Layer Depletion

• Ozone depletion refers to the thinning of the ozone layer due to chemical compounds (bromine, chlorine) released from human activities.

Geosphere

• Shell of rocky planet reaching up to 6,400 km, consisting of the crust, mantle, outer core, and inner core.

Earth's Major Layers

• Crust: Outermost layer, with 98% composed of eight elements including oxygen and silicon; split into oceanic and continental crust.
• Mantle: Largest layer by volume (82%), made of iron, magnesium, and silicon; dense and semi-solid with key discontinuities (Mohorovicic, Gutenberg, Bullen).
• Outer Core: Liquid layer composed mainly of iron and nickel.
• Inner Core: Solid inner part made primarily of iron and nickel.

Biosphere

• Encompasses all living organisms (animals, plants, microbes) and exists approximately within 1 km of Earth’s surface.
• Anthroposphere: Human sphere, representing areas modified by human activity.

This quiz explores the four interconnected spheres of the Earth: lithosphere, hydrosphere, atmosphere, and biosphere, with a focus on the hydrosphere. Understand the significance of water and its role in the Earth's system, including the water cycle and its presence in various states. Test your knowledge on the Earth's surface and the dynamics of water.