Atmospheric Heating

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Transcript Atmospheric Heating

ATMOSPHERIC HEATING
Day 1
All matter is made of atoms
• Matter: anything that has mass and
occupies space
• Atom: the smallest particle of a
substance that can exist by itself or be
combined with other atoms to form a
molecule.
• Molecules: groups of atoms
Temperature vs. Heat
Temperature
• How fast atoms/molecules
move.
• Faster movement =
higher temperature
• Slower movement = lower
temperature
Heat
• Transfer of heat energy
between substances with
a different temperature.
• Energy ALWAYS transfers
from the object with the
higher temperature to the
object with the lower
temperature.
Situations where heat is transferred
ATMOSPHERIC
HEATING
Unit 5: Sixth Grade
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Imagine ….
• You are lying in a park with your eyes closed….. You feel
the warmth of the sun on your face….
• What are you thinking about ….
• Is it the fact that it takes a little more than 8 minutes for
the energy that warms your face to travel from a star that
is 149,000,000 km (93 million miles) away?
• I thought so!
Energy in the atmosphere
• In the scenario, your
face was warmed by
energy from the sun.
• Earth and its
atmosphere are also
warmed by energy
from the sun.
• Today we will find out
what happens to solar
energy as it enters the
atmosphere
Radiation: Energy Transfer by Waves
• The Earth receives
energy from the sun by
radiation.
• Radiation is the
transfer of energy as
electromagnetic waves
Radiation: Energy Transfer by Waves
• Although the sun radiates
a HUGE amount of energy,
Earth receives only 2
billionths of this energy.
• By this small fraction is
enough to drive the water
cycles and weather cycles.
• The Earth is habitable
because of the energy we
receive from the sun
• Think of: standing in front
of a fire
HEAT TRANSFER
Day 2
What happens to the energy once it
enters the atmosphere?
• Energy from the sun is absorbed by the atmosphere, land,
and water is changed into thermal energy
• 20% is absorbed by the ozone, clouds, and atmospheric
gasses
• 25% is scattered and reflected by clouds and air
• 5% is reflected by the earth’s surface
• 50% is absorbed by the earth’s surface.
Conduction: Energy Transfer by Contact
• Thermal conduction is
the transfer of heat
through a material.
• Transferred by touch.
• Thermal energy is
always transferred
from warm to cold
areas.
• Think of: “the other
side of the pillow”
Conduction: Energy Transfer by Contact
• When air molecules
heated by the sun’s
rays (radiant transfer)
come into direct
contact with surface of
the earth, thermal
energy is transferred
Convection: Energy Transfer by
Circulation
• Convection is the
transfer of thermal
energy by circulation or
movement of a liquid or
gas
• Most of the energy in our
atmosphere is
transferred by
convection.
• Think of: standing in
front of a fan while it is
blowing
Convection: Energy Transfer by
Circulation
• As air is heated, it
becomes less dense and
rises.
• Cool air is denser, and it
sinks.
• As the cool air sinks, it
pushes the warm, less
dense air up.
• This cycle of warm air
rising and sinking
causes a circular
movement of air called a
convection current
The Greenhouse Effect
• http://glencoe.mcgraw-
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As you know, 70% of the radiation that enters Earth’s
atmosphere is absorbed by the clouds and the earth’s surface.
This energy is converted into thermal (heat) energy that warms
the planet.
Most of this energy will escape back into space, but our
atmosphere works as a blanket that traps enough energy to
make Earth livable.
This process is called the Greenhouse Effect.
Just like a greenhouse’s glass walls, the gases of our
atmosphere allow heat in, but prevents all of the heat from
escaping
The Greenhouse Effect
Radiation Balance
• For the earth to remain
livable, the amount of
energy from the sun let
in by the atmosphere
needs to be
approximately equal to
the amount that is let
back out into space.
• This balance of incoming
and outgoing is called
radiation balance.
Greenhouse Gases and Global Warming
• Human activities such as burning fossil fuels and
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deforestation may be increasing the gases that trap in
more thermal heat than is necessary for life to exist on
Earth.
Some scientists say these activities are causing average
global temperatures to rise.
This increase in average global temperature is called
global warming.
Scientists fear that this warming could affect plants and
animals on Earth.
This subject is highly complex and debatable!
Smoke from burning rainforests
From eye level
When the smoke clears….