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16-1 Energy in Earth’s Atmosphere (pages 542–545) 1. State in what form energy travels from the sun to the earth. 2. Explain what happens to the sun’s energy in the atmosphere and at Earth’s surface.
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16-1EnergyinEarth’s Atmosphere (pages 542–545)1. State in what form energy travels from the sun to the earth.2. Explain what happens to the sun’s energy in the atmosphere and at Earth’s surface.
EnergyFromtheSun (pages542–543)1. State in what form energy travels from the sun to the earth. KeyConcept:Mostoftheenergyfromthesuntravelsto Earth in the form of visible light and infraredradiation.A small amount arrives as ultravioletradiation.
EnergyfromthesuntravelstoEarthaselectromagneticwaves.Electromagneticwaves are a form of energythat can travel through space.
Electromagnetic waves are classified according to theirwavelengths.
Radiationis the direct transfer of energy byelectromagnetic waves.
Infraredradiationhaswavelengthsthatarelongerthanvisible light.You cannot see infrared radiation, but you can feel it as heat.
Ultraviolet radiationhas wavelengths that are shorterthan visible light.Ultravioletradiation causes sunburn.
EnergyintheAtmosphere(page544)2. Explain what happens to the sun’s energy in the atmosphere and at Earth’s surface. Key Concept:Some sunlight is absorbed or reflectedbytheatmospherebeforeitcanreachthesurface.Therest passes through the atmosphere to the surface.
Partofthesun’senergyisabsorbedbytheatmosphere.When energy is absorbed, it is taken in by a substance.Forexample,watervaporandcarbondioxideabsorbthesome of the sun’s energy.
Part of the sun’s energy is reflected back into space.When energy is reflected, it bounces off without being absorbed.Clouds reflect some sunlight back into space.
Dust particles and gases in the air reflect light in alldirections.Reflecting light in all directions is calledscattering.
About half of the sun’s energy passes through the atmosphere to Earth’ssurface.
2. Explain what happens to the sun’s energy in the atmosphere and at Earth’s surface.Key Concept: When Earth’s surface is heated, it radiates most of the energy back into the atmosphere as infrared radiation.
The energy that reaches Earth’s surface heats the land and water.
The surface of Earth is heated by the sun. The heated surface then radiates the heat back into the atmosphere. The radiation from Earth’s surface is infrared radiation.
Some of the infrared radiation from Earth’s surface is taken in by gases in the atmosphere. The gases that take in this heat include carbon dioxide and water vapor. When gases hold heat in the air, it is called the greenhouse effect.
The greenhouse effect is natural. Because of the greenhouse effect, Earth’s average temperatures remain about the same.
Greenhouse effect radiates Earth gases