Ch. 2 Questions for Review
3.) Explain how heat is transferred in our atmosphere by: (a) conduction, (b) convection, (c) radiation.
(a) Conduction: the process of energy being transferred between surfaces that are in contact with each other. It is the heat transfer from molecule to molecule within a substance. -heat always flows from warmer to colder regions. (b) Convection: the process of air or water transferring heat. It is the heat transfer due to mass movement of a liquid or gas. -Horizontal: wind. -Vertical: Thermals. -in convection, the whole atmosphere is moving, not just single molecules like conduction. - this process happens frequently in the atmosphere on warm days. -energy heats the earths surface and those air molecules closest to the surface move faster up into the cooler air. The cooler air is denser than warm air and thus sinks to the place the warm air rose from. This vertical exchange of heat is known as convection. (c) Radiation: energy in the form of waves that travel through the atmosphere. It is the heat transfer without actually needing a solid, liquid, or gas. -thought of as waves of energy (electromagnetic) or as photons, streams of particles as packets of energy.
TE-8.) Why does the surface temperature often increase on a clear, calm night as a low cloud moves overhead?
Carbon dioxide and water vapor are the two most abundant gases that help in warming the earth. The two help to make up cloud cover in the atmosphere, and absorb the radiation emitted by the sun and earth, increasing surface temperature. On a clear night, when a cloud passes over, there would be a local greenhouse effect. The clouds will deflect the IR radiation coming from the earth back down to the surface, which would then warm the surface, leading to an increased temperature.
8.) How do the wavelengths of most of the radiation emitted by the sun differ from those emitted by the surface of the earth?
Radiation is emitted in waves with specific wavelength. Gamma rays have the shortest wavelength and the most energy, where as radio waves have the longest wavelength and the least energy. The sun is extremely hot and emits lots of energy. The energy can be radiation in any wavelength. However, bodies that are cooler, like the earth, release shorter wavelength radiation, such as infrared.
TE-5.) Which do you feel would have the greatest effect on the earth's greenhouse effect: removing all of the CO2 from the atmosphere or removing all of the water vapor? Explain your answer.
Removing water vapor would most likely have a greater effect. Earth cannot survive without water vapor. Removing water vapor would have the greatest effect on lush, tropical areas etc.
TE-6.) How would the seasons be affected where you live if the tilt of the earth's axis increased from 23.5 degrees to 40 degrees ?
Seasons are created when the Earth is tilted towards or away from the sun, not necessarily by the distance between the sun and the Earth. If the tilt of the Earth was increased, all seasons would become more extreme. During summer in the Northern Hemisphere, the Earth would be closer to perpendicular with the sun, and thus, the sun's rays would have a more direct path towards the Earth, and more radiation would be absorbed. In the winter, the Northern Hemisphere would be tilted much more away from the sun and would be closer to parallel, all less radiation, and less heat to warm the earth.
TE-10.) Explain (with the aid of a diagram) why the morning sun in the Northern Hemisphere shines brightly through a south-facing bedroom window in December, but not in June.
Seasons are created when the Earth is tilted towards or away from the sun, not necessarily by the distance between the sun and the Earth. In the northern hemisphere during January, the earth is physically closer to the sun, but it's tilted away from it. The tilt of the earth causes the sun to radiate energy through a thicker layer of the atmosphere. This means more solar radiation is reflected, and thus creates cooler temperatures. Since the sun is entering the atmosphere at a different angle during each season, the sun would only enter a southern-facing window during the winter. During December, the sun is entering at a lower, less direct angle from the south. In the summer, the sun's rays enter the atmosphere almost perpendicular to earth. This means the sun is rising almost directly above the house and would not shine through the southern window.
10.) Why are carbon dioxide and water vapor called selective absorbing greenhouse gases?
Selectively absorbing greenhouse gases only absorb some wavelengths of radiation. The earth acts as a blackbody and absorbs all wavelengths. Carbon dioxide and water vapor are the two most important absorbers of radiation. They absorb radiation given off by the earth and sun. They trap heat in the atmosphere and are known as greenhouse gases. However, they allow the visible solar radiation from the sun to reach the earth. So, they allow in radiation from the sun, and absorb radiation given off by the earth, which is what helps warm the earth.
15.) How is the lower atmosphere warmed from the surface upward?
The earth absorbs radiation given off by the sun. This radiation is later released by the earth through processes such as evaporation. The radiation released from earth is known as infrared (IR) radiation. As the infrared radiation travels up through the air, gases in the lower atmosphere, such as carbon dioxide and water vapor, trap the energy in the lower atmosphere, warming it.
