Download Air energy Earth Science II

Air energy
Earth Science II
(Session 3)
Air energy
• The air’s energy can be
transmitted by three different
mechanisms:
– Convection
– Conduction
– Radiation.
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Convection
• Convection: is
the transmision
of heat by
materials that
flow such as
gases and
liquids.
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Convection
• Heat is transferred by the
movement of gasses from a
higher temperature to a region
with a lower temperature.
• Convection requires the mobility
of the environment and
accelerates by means of
agitation.
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The fresh ocean breeze
during the day
• Why is there a nice breze
when you dgo to the beach?
• What is happening to the air
on the ground versus the air
over the ocean?
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The fresh ocean breeze
during the day
• On a hot day, the air over the
ground heats up faster than the air
over the water.
• The colder ocean air moves from
the ocean to the beach, generating
a fresh ocean breeze during the
day.
• What happens to the flow of air
after the sun sets?
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Ocean breeze at night
• After dawn, the ground cools
more quickly than the water,
the direction of air currents
invert, that is to say, the air
moves from the beach to the
ocean.
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• The process of
convection is
completed
mostly in the
atmosphere.
• What are some
other examples
of convection?
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Ascendening currents
• On sunny days, the ground and
rocks are heated by the rays of
the sun.
• The rocks transfer heat to the air
that surround them; this hot air
rises and is cold air takes its
place.
• That cold air will eventually heat
up.
• This process happens over and
over again forming ascending
currents that can be pretty strong.
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Ascending Currents
• Air plane pilots look for
Ascending currents to reach
high altitudes and maintain
flight for their apparatus.
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Conduction
• Conduction: is the direct transmission of heat
from one particule to another.
Molecules
Solid Material
Flow of energy
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Conduction
• Is the mechanism thru which thermal
energy transfers without macroscopic
movement of the environment that
conducts the flow of heat.
• Air presents a very low thermic
conductivity.
• In the air, the heat by conduction is
transferred when molecules that form it
crash between themselves or with the
surface they are exposed to.
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Radiation
• Radiation: is the energy that can be
transmitted through an empty space.
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Radiation
• Is the constant flow of energy that
comes from the sun (ultraviolet,
infrared light, etc.)
• Thermal radiation, like light, consists
of electrmagnetic waves similar to
radio, TV and radar waves.
• The transfer of energy by radiation
does not need a material means, it
travels through space with wave like
movements.
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Class reading
• From your textbook…
– Science and You: Protecting
yourself from the sun.
– Page 400
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Added Material
• Page: Action unit by Ozone
• Page: Earth Observatory
– Virtual laboratory of the ozone
layer
– Virtual laboratory of solar radiation
– Virtual laboratory of heat radiation
– Virtual laboratory of neta radiation
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Bibliography
• DiSpezio, M. et al. (1999).
Science Insights: Exploring
Earth and Space. first ed. USA:
Prentice Hall.
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