1. Earth Science II (Session 3)
Air energy
Earth Science II
(Session 3)

2. Ciencias de la Tierra II
Air energy
The air’s energy can be transmitted by three different mechanisms:
Convection
Conduction
Radiation.
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3. Ciencias de la Tierra II
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.
Ciencias de la Tierra II

5. 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?
Ciencias de la Tierra II

6. 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.
Ciencias de la Tierra II