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• Types of systems

  • Isolated
  • Closed
  • Open
• Isolated system


  A system that does not allow matter and energy to leave or enter
• Closed system


  A system that will enable energy to enter and leave but does not allow the matter to go
• Open system


  A system that will enable both energy and matter to enter and leave
• The Earth, the only habitable planet, is essentially a closed system where there is only an exchange of heat and energy but no exchange of matter
• Heat and energy are transferred from the Sun to the Earth, and within the Earth, they are transferred between subsystems
• Earth's subsystems

  • Geosphere (land)
  • Atmosphere (air)
  • Hydrosphere (water)
  • Biosphere (living organisms)
• The subsystems of the Earth are open systems because matter and energy can flow across the boundaries between subsystems
• Geosphere


  • The plates are the outer crust of the Earth that are broken down into pieces, and they make up the 30% of the Earth's surface
  • These plates can move around against each other, they can either collide, move away from each other, or slide past each other
  • This geological activity is very important in the carbon cycle process
• When microscopic plants die in the ocean, they fall to the bottom of the ocean, buried over time, then are carried back into the interior of the Earth by volcanoes and recycled. This pulls carbon out of the atmosphere, which makes sure we do not suffer greenhouse effect
• Greenhouse effect


  The process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without this atmosphere
• Carbon cycle


  The biogeochemical cycle by which carbon is exchanged among the biosphere, geosphere, hydrosphere, and atmosphere of the Earth
• Layers of the Geosphere

  • Crust
  • Mantle
  • Core
• Crust


  • The thinnest layer of the Earth
  • Further divided into continental and oceanic crust
  • Continental crust is mainly made up of granite rocks
  • Oceanic crust is mainly made up of volcanic rocks called basalt
• Mantle


  • The thickest layer of the Earth (2,900 km thick)
  • Comprises of hot, dense rocks
  • There is a great difference in temperature between the lower and upper mantle
  • The plates "float" on it like how oil floats on water
  • This "float" is described as convection currents that happen in the asthenosphere
• Core


  • The hottest layer located at the center of the Earth
  • Consists of solid and molten metals
  • Outer Core is so hot (between 4,500°C and 5,500°C) that the metals are all liquid
  • Inner Core is a solid sphere composed mostly of iron metal
• About 200 million years ago, the continents were joined together in a huge landmass called Pangaea, as proposed by Alfred Wegener
• Pangaea as a supercontinent broke apart and gradually drifted to its present position
• Plate tectonic theory


  The lithosphere is divided into major plates resting upon the lower soft layer called the asthenosphere<|>The mechanism of movement of the plates is related to the convection current within the mantle
• The lithosphere is also driven by erosion, weathering, and transport, as well as by tectonic forces and volcanic activity, which results in landforms such as mountains, hills, and plateaus
• Pangea's existence was first proposed in 1912 by German meteorologist Alfred Wegener as a part of his theory of continental drift
• Atmosphere


  A gaseous envelope held by gravity that surrounds the Earth<|>Without the Atmosphere, the Earth would be like a bigger version of the moon – cold and lifeless
• Composition of the Atmosphere

  • 78% nitrogen (N)
  • 21% oxygen (O)
  • 0.9% argon (Ar)
  • Trace amounts of greenhouse gases such as hydrogen (0.00005%), helium (0.0005%), carbon dioxide (0.038%) and others
• Layers of the Atmosphere

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere
• The Atmosphere receives energy from the Sun. Some of the heat and energy from the Sun is trapped and absorbed by gases that warm the Earth's surface, while some are reflected in space
• The Atmosphere also protects the Earth from the harmful radiation and rays coming from the Sun
• Among all the planets in the solar system, only Earth has a breathable atmosphere that allows life to exist
• Meteorites


  Solid pieces of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon
• Ozone


  An inorganic molecule with the chemical formula O3
• Ultraviolet light


  UV radiation present in sunlight, constituting about 10% of the total electromagnetic radiation output from the Sun
• Effects of UV light

  • Suntan
  • Sunburn
  • Increased risk of skin cancer
• Hydrosphere


  Includes all the liquid, gaseous (water vapor), and solid (ice) water of the planet Earth
• About 70% of the Earth is covered with liquid water (Hydrosphere), and 97% of it is in the form of ocean water
• Only 3% of Earth's water is freshwater: 79% is frozen or stored in ice caps and glaciers, 20% is stored beneath the ground, and only 1% is easily accessible on lakes and other water sources
• Water is essential for the existence and maintenance of life on Earth
• The Hydrosphere is driven by the water cycle processes, which enable water to be recycled and moved around Earth
• Biosphere


  Contains all the living organisms that inhabit the Earth, including plants, animals, microorganisms, and humans
• Within the Biosphere, living organisms form communities called biomes filled with many ecosystems
• The Biosphere is closely related to the other subsystems of the Earth because most living organisms require gases from the Atmosphere, water from the Hydrosphere, and nutrients and minerals from the Geosphere
• Life on Earth is ubiquitous; there are organisms we can find in boiling springs, the deepest part of the oceans, and the coldest part of the world