Section 2 Energy in the Earth System
System
- an organized group of related objects or components
that interact to create a whole
- vary in size (subatomic to universe)
- all have boundaries
- Earth system is an interaction between matter and
energy
o Matter – anything that has mass and volume
o Energy – the ability to do work
 Heat
 Light
 Vibrations
 Electromagnetic waves
Closed system – energy is exchanged, not matter
Open system – both energy and matter are
exchanged
Earth system is almost closed because matter
exchange is very limited
Earth’s Four Spheres
Atmosphere
- blanket of gases that surrounds Earth’s surface
- provides the air that you breath
- shields Earth from sun’s harmful radiation
- 78% nitrogen, 21% oxygen and 1% a mixture of gases
Hydrosphere
- all of Earth’s water except the water that is in gaseous
form in the atmosphere
- 71% of Earth’s surface is covered
- 97% of water is in salty oceans
Geosphere
- mostly solid part of the Earth
- all of the rock and soil on the surface and on the ocean
floor
- includes the solid and molten interior of the Earth
Biosphere
- composed of all of the forms of life in the geosphere, in
the hydrosphere, and in the atmosphere
- any organic matter that has not decomposed
- extends from the deepest parts of the ocean to the
atmosphere a few kilometers above Earth’s surface
Earth’s Energy Budget
First law of Thermodynamics
Energy Budget
Second law of Thermodynamics
Internal Energy Sources
- decay of radioactive atoms
- convection – movement of hot materials toward the
surface
o cooler, denser materials sink
o this process drives plate tectonics
External Energy Sources
- sun
o movement of air masses
o generates wind and ocean currents
o allows plants to produce food
- the pull of the sun and the moon on the oceans,
combined with Earth’s rotation, generates tides that
cause currents and drive the mixing of ocean water
Cycles in the Earth System
Reservoir – a place where matter and energy is stored
Cycle – a group of processes in which matter and energy
repeatedly move through a series of reservoirs
- Nitrogen Cycle – nitrogen moves from air to soil, soil to
plants and animals and back to air again
- Carbon Cycle
- Phosphorous Cycle – moves through every sphere
except the atmosphere
- Water Cycle – water to gas to precipitation to water