Atmosphere

The Atmosphere a mixture of gases that surrounds a planet insulates Earth - keeps it at a temp. at which living things can survive protects the Earth’s surface from harmful UV rays

Composition of the Earth’s Atmosphere 78% nitrogen 21% oxygen 1% other gases such as argon, carbon dioxide, methane, and water vapor atmospheric dust

Atmosphere Can Change pollutants mix with oxygen and other chemicals to form smog increasing human energy use is increasing the amount of carbon dioxide gases can be added to and removed from the atmosphere through living organisms volcanic eruptions

Layers of the Atmosphere The Troposphere The Stratosphere The Mesosphere The Thermosphere

Layers of the Atmosphere

The Troposphere lowest layer – closest to the Earth where weather occurs densest layer – thins at higher altitudes making breathing more difficult

The Stratosphere

The Mesosphere 3 rd layer coldest layer of the atmosphere - temps as low as –93ºC where meteors or rock fragments burn up

The Thermosphere 4 th layer - located furthest from Earth’s surface temps measuring above 2,000 ºC would not feel hot – air so thin that particles rarely collide to transfer heat (there’s a difference between temp. and heat) contains ionosphere - electrically charged atoms that radiate energy as light – the Northern and Southern Lights

Energy Transfer in the Atmosphere Radiation - transfer of energy across space and in the atmosphere ex. feeling heat from sun or fire Conduction - transfer of energy as heat from a warmer object to a colder object when in contact; ex. food cooking in a pan Convection - transfer of heat by air currents – warm air rises and cold air sinks; ex. water boiling or lava lamp

Energy Transfer in the Atmosphere

The Greenhouse Effect greenhouse effect (GHE) - the warming of the surface of the Earth due to the insulating effect of the gases in the atm. (GHGs – Greenhouse Gases) GHGs absorb and reflect the sun’s energy/heat GHE is natural without GHE, Earth would be too cold for life to exist quantities of GHGs vary as a result of natural and industrial processes

The Greenhouse Effect GHGs trap heat near Earth’s surface just the way windows of a car trap heat in the car Greenhouse Effect

Greenhouse Animation

Global Warming Occurs when there are too many GHGs caused by human activities - increased GHGs from burning fossil fuels and pollution Global warming is NOT good!  over the past 50 years the average global temp. has increased at the fastest rate in recorded history  Global climate change - loss of sea ice, accelerated sea level rise and longer, more intense heat waves and storms  Changes in ecosytems

Review 1.How much nitrogen is in the Earth’s atmosphere? How much oxygen is in the Earth’s atmosphere? 2. In which layer of the Earth does weather occur? 3. Why should we care if the ozone layer is destroyed? 4. Which layer is the coldest and the hottest? 5. What is something interesting about the thermosphere? 6. Fill in the blanks using the correct form of heat transfer a)The transfer of heat through material by direct contact is ____________.

b)______________________ is the transfer of heat in a fluid (gas or liquid) as a result of the movement of the fluid itself. c) What kind of heat transfer does the sun use? (hint: it transfers heat via electromagnetic waves through space). _________________________ 7. In each of the following situations, identify the method of heat transfer taking place. a. Near the ceiling of a room the air is warmer. The warm air rises because of.. __________ b. A student holds the back of his hand near a beaker to see if it is hot. Heat is transferred to his hand by…… __________

c. A certain type of stainless steel cookware has a layer of copper applied to the bottom to help it heat evenly. The copper transfers heat to the pan by …………….. __________ d. A house burns down. On the house across the street, all of the vinyl siding is twisted and warped by the heat. The heat was transferred across the street by…….. __________

8. An alien from another planet has just arrived and is perplexed by the controversy surrounding the greenhouse effect and global warming. Here’s how you can help: Task 1: Draw a diagram illustrating the greenhouse effect. Label it carefully. Task 2: Below your diagram write a concise paragraph that explains the diagram and how the greenhouse effect and global warming are alike and different.