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UNIT THREE: Matter, Energy, and Earth. Chapter 8 Matter and Temperature Chapter 9 Heat Chapter 10 Properties of Matter Chapter 11 Earth’s Atmosphere and Weather. Chapter Eleven: Earth’s Atmosphere and Weather. 11.1 Earth’s Atmosphere 11.2 Weather Variables
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UNIT THREE: Matter, Energy, and Earth • Chapter 8 Matter and Temperature • Chapter 9 Heat • Chapter 10 Properties of Matter • Chapter 11 Earth’s Atmosphere and Weather
Chapter Eleven: Earth’s Atmosphereand Weather • 11.1 Earth’s Atmosphere • 11.2 Weather Variables • 11.3 Weather Patterns
Key Question: How does solar radiation affect the heating and cooling of continents and oceans? Investigation 11A Heating Land and Water
11.1 Learning Goals • Describe the composition of Earth’s atmosphere. • Explain the meaning of atmospheric pressure and describe how it is measured. • Identify the layers of Earth’s atmosphere and discuss unique characteristics of each layer.
11.1 The Atmosphere • Earth’s atmosphereis a layer of gases surrounding the planet, protecting and sustaining life. • It insulates us so that we don’t freeze at night. • Its ozone layer protects us from the sun’s ultraviolet rays. • It also contains the carbon dioxide needed by plants for photosynthesis, and the oxygen we need to breathe.
This wonderful protective layer exists around Earth because our planet has just the right balance of size and distance from the sun. Nitrogen gas makes up about 78 percent of Earth’s atmosphere. The second most abundant gas is oxygen, which makes up 21 percent of Earth’s atmosphere. 11.1 What's in Earth's atmosphere?
11.1 Nitrogen Cycle • Nitrogen is important to protein which is found in the body tissues of all living things. • Nitrogen is cycled through the soil and into plants and finally when living things die and decay.
11.1 Why is Earth different? • The atmospheres of Venus, Earth, and Mars were formed in similar ways, so we might expect them to contain similar elements. Photosynthesis changed Earth’s atmosphere.
Photosynthesis and the atmosphere • Photosynthesis converts carbon dioxide to oxygen in a process that allows living things use the sun’s energy.
11.1 Earth stores carbon • Many marine organisms such as microscopic phytoplankton use carbon dioxide dissolved in seawater to form shells of calcium carbonate.
11.1 Atmospheric pressure • Atmospheric pressure is a measurement of the force due to air molecules at a given altitude. • The pressure of the atmosphere decreases as you rise above sea level.
11.1 Atmospheric pressure • At sea level, the weight of the column of air above a person is about 9,800 newtons (2,200 pounds)! • This is equal to the weight of a small car. • Why aren’t we crushed by this pressure?
A barometer is an instrument that measures atmospheric pressure. Long ago, mercury barometers were used. 11.1 Measuring Pressure
11.1 Layers of the Atmosphere • Four Layers • Thermosphere • Mesosphere • Stratosphere • Troposphere*
Troposphere:where we live • Stratosphere:contains the ozone layer • Mesosphere: where the temperature is coldest • Thermosphere,where the temperature is highest 11.1 Our Atmosphere
Other layers • The ionosphere is part of the thermosphere and is where the Sun’s ultraviolet light creates charged atoms and molecules called ions. • The exosphere begins at about 500 kilometers above Earth’s surface and does not have a specific outer limit.
