Transcript Earth as a System - Leon County Schools

Chapter 2
Notes
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1-Earth Basics
2-Earth’s Interior
3-Compositional Zones
4-Structural Zones
5-Earth as a Magnet
6-Gravity and the Earth
7-Earth System
8-Earth’s 5 Spheres
9-Energy Budget
10-Nitrogen Cycle
11-Carbon Cycle
12-Phosphorous Cycle
13-Water Cycle
14-Ecosystems
15-Energy Pyramid and Food Webs
16-People and the Earth
 third
planet from the sun
 about 4.6 billion years old and is made mostly of
rock.
 about 71% of Earth’s surface is covered by a thin
layer of water (global ocean).
 an oblate spheroid, or a slightly flattened sphere.
Earth’s pole-to-pole circumference is 40,007 km.
Its equatorial circumference is 40,074 km.
 average diameter is 12,756 km.
 Brain POP:
http://www.brainpop.com/science/earthsystem/
earth/
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Scientists use seismic waves to learn about
the interior (earthquakes or explosives)
three major compositional zones and five
major structural zones.
Brain POP:
http://www.brainpop.com/science/earthsyste
m/earthsstructure/
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crust the thin and solid outermost layer of
Earth above the mantle
Oceanic crust, which lies under the oceans, is
only 5 to 10 km thick.
The continental crust varies in thickness from
15 km to 80 km.
mantle in Earth science, the layer of rock
between Earth’s crust and core- nearly 2,900
km thick and makes up almost two-thirds of
Earth’s mass.
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core the central part of Earth below the
mantle-composed of nickel and iron, radius
is about 3,500 km.
See TB pg.30
five structural zones
 lithosphere the solid, crust and the rigid
upper part of the mantle, 15 to 300 km
thick.
 asthenosphere the solid, plastic layer of the
mantle beneath the lithosphere; made of
mantle rock that flows very slowly, which
allows tectonic plates to move on top of it,
about 200 to 250 km thick.
five structural zones
 Mesosphere-the “middle sphere”; the strong,
lower part of the mantle between the
asthenosphere and the outer core, thickness
of about 2,900 km.
 Below the mesosphere is the liquid outer
core.
 The outer core surrounds the solid inner
core, which begins at a depth of 5,150 km.
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Earth’s magnetic field extends beyond the
atmosphere and affects a region of space
called the magnetosphere
Scientists think that motions within the liquid
iron of Earth’s outer core produce electric
currents that in turn create Earth’s magnetic
field.
Gravity -force of attraction that exists
between all matter in the universe.
 depends on the masses of the objects and the
distance between the objects. (Newton’s law
of gravitation)
(so the larger the masses of two objects and
the closer together that the two objects are,
the greater the force of gravity between the
objects will be)
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Weight is a measure of the strength of the
pull of gravity on an object.
Weight is a force
An object’s weight depends on its mass and
its distance from Earth’s center.
(Interesting note: Because the distance
between Earth’s surface and its center is
greater at the equator than at the poles, the
weight of an object at the equator is about
0.3% less than its weight at the North Pole.)
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Matter is anything that has mass and takes up
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Energy is defined as the ability to do work.
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space.
(Energy can be transferred in a variety of
forms, including heat, light, vibrations, or
electromagnetic waves.)
A system can be described by the way that
matter and energy are transferred within the
system or to and from other systems.
Open Systems
 An open system is a system in which both
energy and matter are exchanged with the
surroundings.
Closed Systems
 A closed system is a system in which
energy, but not matter, is exchanged with
the surroundings.
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Technically, all systems that make up the
Earth system are open, but matter exchange
is limited.
Energy enters the system in the form of
sunlight and is released into space as heat.
Note: Only a small amount of dust and rock
from space enters the system, and only a
fraction of the hydrogen atoms in the
atmosphere escape into space.
The Atmosphere
The Hydrosphere
The Cryosphere
The Biosphere
The Geosphere
The Atmosphere:
 a mixture of gases that surrounds a planet,
moon, or other celestial body
 provides the air you breathe
 shields Earth from the sun’s harmful
radiation
The Hydrosphere
 the portion of the Earth that is water
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97% of this water is contained in the salty
oceans. The remaining 3% is fresh water.
The Cryosphere
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Frozen water on the Earth (water in solid
form)
Glaciers, icebergs, snow
The Geosphere
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mostly solid, rocky part of the Earth
Rock, soil, solid and liquid rock layers of
earth.
The Biosphere
 includes all of the living organisms on Earth
 (The biosphere is composed of all of the
forms of life in the geosphere, in the
hydrosphere, and in the atmosphere, as well
as 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.
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The transfers of energy between Earth’s
spheres can be thought of as parts of an
energy budget.
Energy cannot be created or destroyed (1st Law
of Thermodynamics)
Energy becomes less organized over timespreads out (2nd Law of Thermodynamics)
The constant exchange of matter and energy
between Earth’s spheres happens through
chemical reactions, radioactive decay, the
radiation of energy, and the growth and decay
of organisms.
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Nitrogen
Carbon
Phosphorous
Water
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Nitrogen in air-soil-plants and animals-air
Nitrogen is removed from air mainly by the
action of nitrogen-fixing bacteria in the soil.
Brain POP:
http://www.brainpop.com/science/earthsyste
m/nitrogencycle/
 Carbon is an essential element for all living things
 Moves through all of the Earth’s spheres
 Enters atmosphere as CO2
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Brain POP: http://www.brainpop.com/science/earthsystem/carboncycle/
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Does not move through the atmosphere-P is
rarely a gas
Sources of Phosphorous: break down of
rock, animal waste
Plants take up P-pass it to animals when
plant is eaten
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Continuous movement of water
Includes evaporation, transpiration,
condensation, precipitation
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Biotic and abiotic components
Can be small or large
Contain producers, consumers and
decomposers
Carrying Capacity: the largest population that
an environment can support
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Shows energy transfer
Food webs are more complex than food
chains
Photosynthesis is used by plants (producers)
to make their own chemical energy from
sunlight
Arrows in food web indicate the direction of
energy transfer
Energy is lost as you
move up the pyramid
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People can change the Earth by altering
ecosystems, introducing pollutants into the
environment and overuse of resources.