1. THE ATMOSPHERE Gases that surround the earth

2.  Mixture of gases such as nitrogen, oxygen, carbon, dioxide  Changes constantly ex: animals breathe in oxygen breathe out carbon dioxide while plants take in carbon dioxide and send out oxygen  Insulates the earth’s surface from the sun’s rays  Question: What is the current concern over our atmosphere and why?

3. What is the mixture?  Nitrogen makes up 78% of the earth’s atmosphere and comes from the decay of plants/animals and volcanic eruptions  Oxygen makes up 18% of the atmosphere and comes from plants  Other gases such as methane, argon, and carbon dioxide make up the rest  As we get closer to the earth the air becomes denser (heavy) as we rise through the layers of the atmosphere, the earth’s air becomes lighter. Provide an example of difficult areas to breathe?

4. Layers The layers are defined by the changes in temperatures and pressure – Troposphere- layer closest to the earth’s surface that provides earth’s weather – Stratosphere-layer where the sun’s ultra violet rays are absorbed in what is called the ozone layer – Mesosphere – coldest layer of the atmosphere at -93 C and located in the middle of the atmosphere – Thermosphere- furthest away from the earth’s surface. Temperature is 2000 C but does not feel as cold because of the separation of the atoms Ionosphere - lower thermosphere the generates heat energy and looks like light in the light skies of the North and South Pole Exosphere – Outer Space

6. Energy of the Atmosphere Air consists of electrons which are particles of energy called ion (atom that has a charge either positive or negative) Ionized air become hot and pushes out air which creates the thunder from the lightening. Sun is changed into energy in the earth’s atmosphere in three ways – Radiation-sun’s energy as it travels across space. Once it hits the earth it is felt as heat – Conduction – is the flow of heat from warmer object to a colder object when place directly in the line of heat – Convection – transfer of heat by air currents

7. As the sun’s ray travel to the earth energy travels as heat to the earth’s surface. As the surface of the earth heats up some of the radiation is absorbed and the rest is reflected back into the atmosphere. Air moves in a circular motion with cooler air sinking and warmer rising. As air warms up for the sun’s rays it rises cools and sinks back down. This constant motion is

8. Atmosphere conditions Tornado – strong storm winds that over land and touch down upon the ground starting in speeds slightly less than 110 mph Hurricane- strong winds that begin out over the sea and travel into land masses with wind speeds beginning at 74 mph Extreme Lightening – travels either up or down. It is a bright flash of light that moves energy through the atmosphere in bright electrical charges