Weather

Weather – is the condition of the Earth’s atmosphere at a particular time and place. Atmosphere – is the layer of gases that surrounds the planet. “blanket” that makes life possible. Composition of the Atmosphere 1.Nitrogen 78% 2.Oxygen 21% 3.Carbon dioxide.036% part of the 1%. 4.Water vapor and many other gases. 1% 5.Suspended particles solid and liquid.

Nitrogen – needed for life. Obtained by the way of nitrogen converting bacteria in plants. We get the nitrogen from the plant in the form of proteins. Oxygen – O 2 is two molecules of oxygen chemically bound together. We must have this in order to have energy and to start a fire. O 3 is Ozone. Carbon Dioxide – Essential for life. To much in the atmosphere causes global warming (from burning).

Other gases – most of which is argon and carbon dioxide. Water Vapor – is a form of a gas. Invisible and can be as little as.0009% or as much as 5% of the air. Water vapor will come out of the air as condensation on a particle in the air (cloud). Particles – solid and liquid particles of dust, smoke, salt, and other chemicals “float” around in the air and this is water vapor “sticks” to in order to form clouds.

Air Quality Air pollution – mostly the result of burning of fossil fuels such as coal, oil, gasoline, and diesel fuel. 1.Solid particles – salt, dirt, pollen, and mold are floating around in the air as natural pollutants. 2.Smog – forms when particles of coal smoke combine with water droplets in humid air. OR when hydrocarbons are not burned completely and bonds with nitrogen in the air to produce photochemical smog.

3.Acid rain – forms when nitrogen oxides and sulfur oxides combine with water in the air to form nitric acid and sulfuric acid. 4.Fixing air pollution – HOW? economy1.htm Properties of air Density – the amount of mass in a given volume. formula for density D=M/V Density = Mass divided by Volume

Pressure – force pushing on an area or surface. The more dense the air the more pressure the air has. Air pressure – Is the result of the weight of a column of air pushing down on an area. Units – inches of mercury inch Hg Millimeters of mercury mmHg Millibars mb Altitude – air pressure decreases as altitude increases. As air pressure decreases, so does air density.

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Measuring air pressure Barometer – is an instrument that is used to measure changes in air pressure. 2 types 1. Mercury barometer – glass tube open at the bottom end and partially filled with mercury. The tube is mostly vacuum sealed. 2. Aneroid Barometer – (without liquid) has an airtight metal chamber that expands and contracts based on the amount of pressure. When it expands and contracts it moves the needle.

Atmosphere layers The four main layers of the atmosphere are classified according to changes in temperature. 1.Troposphere – lowest or closest layer to Earth. “Tropo” means changing. Earth’s weather occurs here. Contains most of the mass of the entire atmosphere. Temp. decreases by 6.5 C for every Km travel upwards, reaching a low of -60 C at the top.

2.Stratosphere – Extends 50 Km above Earth. Strato means to layer or flatten. The temp. warms up toward the top due to the Ozone absorbing heat from the suns light energy. 3. Mesosphere – from 50 km to 80km above the Earth. Meso means middle. The coldest part of the atmosphere -90 C. This layer protects us from objects that try to fall to Earth. When they hit this layer they burn up.

4.Thermosphere – At the top of the atmosphere with very thin air. Starting at 80km above Earth and extending outward into space. Thermo means heat. Temp. reaches 1800 C. - Ionosphere – is the lower part of the thermosphere. - Exosphere – is the upper part of the thermosphere.