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The Air Around You Chapter 7.1

The Air Around You Chapter 7.1

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The Air Around You Chapter 7.1

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  1. The Air Around YouChapter 7.1

  2. Atmosphere The Earth has gases all around. This layer of gas surrounding the earth is called the atmosphere.

  3. What does the atmosphere do for us? Earth’s atmosphere makes conditions on Earth suitable for living things. Contains gases we need to live Traps energy from the sun and keeps the Earth Warm enough for water to exist as a liquid. Protects biotic factors from radiation from the sun. Prevents earth from being hit by most meteoroids.

  4. Composition of the Atmosphere Nitrogen 78% Oxygen 21% Argon 0.93% Carbon Dioxide 0.038% Water Vapor (varies) N O A C

  5. Troposphere Stratosphere Mesosphere Thermosphere Ionosphere Exosphere Taste Sweet Melon That Is Excellent! Troposphere – Weather occurs. Airplanes fly just above the clouds Stratosphere – The Ozone layer absorbs ultraviolet light Mesosphere – meteoroids burn up here producing meteor trails Thermosphere: Ionosphere – Aurora borealis occurs here Exosphere- satellites orbit Earth. Mr. Lee - Layers of the Atmosphere rap 7.3 Layers of the atmosphere pg. 269

  6. Ozone Layer The Ozone Layer is a layer of O3 molecules that is found in the stratosphere. The ozone layer protects us from harmful UV light from the sun.

  7. What is causing ozone depletion?

  8. In 1978 the U. S. Government banned the use of certain CFCs, and manufacturers of aerosol products had to find other propellants. Some of the alternative propellants include hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and carbon dioxide. In 1987 an international treaty known as the Montreal Protocol on Substances that Deplete the Ozone Layer decreed that CFC use should be decreased. Two years later 93 nations agreed to stop producing CFCs entirely and help poorer nations make the transition to other chemistries. • Now less than two percent of American-made aerosol cans contain CFCs. Those that do contain CFCs mostly dispense drugs, such as asthma inhalers. The other chemical compounds that have been developed to replace CFCs thus far are more expensive and less versatile. One promising alternative propellant is Polygas, developed by Scottish inventor Bernard D. Frutin. This mixture of carbon dioxide and acetone is reportedly superior to other propellants because it is more environmentally sound, less flammable, and creates higher and more consistent pressure.