Chapter 15 Characteristics of the Earth’s Atmosphere Standard S6E3.b: The relationship between the atmosphere and the water cycle Standard S6E4.b: The effects of unequal heating on weather patterns
Section 1: pp. 448-453 EQ: What is the composition of Earth’s atmosphere? • Atmosphere • Mixture of gases that surrounds the planet or moon • Nitrogen—78% from decomposition of dead organisms • Oxygen—21% released from plants • Other gases—1% from carbon dioxide, argon, water vapor, etc.
EQ: Why does air pressure change with altitude? • Air Pressure • The measure of how much force air molecules push down on a surface • Decreases with altitude & is less dense
EQ: How does air temp. change with atmospheric conditions? • Result of composition of the atmosphere • Some gases absorb more solar energy & cause an increase in temp.
EQ: What are the 5 layers of the atmosphere? • Thermosphere • Mesophere • Stratosphere • Upper most layer • Molecules are extremely far apart • Hottest layer • Coldest layer • Temp. increases at the top of the layer • Contains the ozone layer that protects Earth from harmful UV solar rays
Troposphre • The layer we live in • Most dense layer with 90% of Earth’s mass • Where weather occurs • May be polluted
Summary • Explain why hot air rises. How does this concept relate to the density of air in the upper levels of the atmosphere?
EQ: How is Earth heated? • Radiation • Transfer of energy as electromagnetic waves from the sun • Earth receives only a tiny fraction , but it’s enough to influence weather
Conduction • Convection: • Transfer of heat by direct contact, by touching • The hot object gives heat to the cooler object. • Transfer of thermal energy by the circulation or movement of a liquid or gas • Hot air rises, cold air sinks • Earth is covered with convection zones
EQ: What is the relationship between the green house effect and global warming? • Greenhouse Effect • Radiation Balance • Gases in the atmosphere, like water vapor and CO2 absorb earth’s heat & then send it back to Earth • Acts like a blanket & keeps the heat in • Equal amounts of heat enter Earth and leave Earth
Global warming • Gradual increase in the average global temperature due too increased CO2 levels • Result of burning fossil fuels, deforestation • Effects plant and animal habitats
Summary • How is the greenhouse effect related to the water cycle? • What might happen to the water cycle as groundwater gases increase?
Section 3 pp. 458-463EQ: What is the relationship between air pressure and wind direction? • Wind • Caused by differences in air pressure • The greater the difference, the faster the wind blows
Air Rises @ the Equator • Air Sinks @ the Poles • Pressure Belts • Warm ,less dense air has low pressure, rises & flows to the poles • Cold, more dense air sinks & flows to the equator • Caused by uneven heating of the Earth every 30 degrees latitude at convection cells
Coriolis Effect • Global Winds • Global winds appear to curve due to Earth’s rotation • Caused by convection cells & Coriolis Effect • Polar Easterlies • Westerlies • Trade Winds
Jet Stream • Narrow belt of strong winds that blow in the upper troposphere & lower stratosphere • Max. speed = 400km/h • Affects the movement of storms • Brings colder air to us if it dips south
EQ: What causes local winds? • Local winds • Move short distances • Can blow from any direction • Local geographic features can create wind
Sea Breeze • Land Breeze • During the day, the cooler air over the ocean forms high pressure • Blows over the land & pushes the warmer land air up • At night, cool land air blows over the warmer ocean air that is pushed up
Valley Breeze • Mountain Breeze • During the day, warm air rises up to the top of the mountain slope • At night, cold air sinks in to the valley
Summary • Draw a graphic organizer to explain sea and land breezes and valley and mountain breezes. Label and use arrows to indicate direction.