Weather

Weather and Atmosphere  Weather- condition of Earth’s atmosphere at a particular time and place  Atmosphere-the envelope of gases that surrounds the planet  Importance of the Atmosphere:  Contains gases needed to survive  Traps energy from the sun to keep the planet warm planet warm  Protection from UV radiation  Protection from meteoroids

Layers of the Atmosphere  Troposphere  Stratosphere  Mesosphere  Thermosphere –Ionosphere –Exosphere  The layers of the atmosphere are classified by changes in temperature

Gases in the Atmosphere  Nitrogen- 78%  Oxygen- 21%  Other gases-1% –Argon –Carbon Dioxide –Neon –Helium –Methane –Krypton –Hydrogen –Ozone

Properties of Air  Volume  Mass  Density  Pressure

Volume  Volume-the amount of space an object takes up  Formulas for calculating: –V = l x w x h (regular shaped objects) –V= V f -V i (irregular shaped objects=water displacement)  Tools to measure-ruler, graduated cylinder  Units –Cm 3, m 3, mL, and L

Mass  Mass-The amount of matter in an object  Tool to measure-triple beam balance  Units –g, kg, mg  Weight = mass + gravity

Density  Density-Mass per unit volume  Formula for calculating: D= M V  Units –g/cm 3, g/mL

Air Pressure  Air pressure-A force resulting from the weight of a column of air pushing down on an area  Force = mass x acceleration –Acceleration due to gravity  Units of air pressure –millibars and inches of mercury  Air pressure pushes on you equally in all directions

Measuring Air Pressure  A barometer is used to measure air pressure  2 types of barometers –Mercury barometer –Aneroid barometer

Altitude  Altitude-elevation or distance above sea level  As altitude increases, the density of the air decreases –the gas molecules that make up the atmosphere are farther apart at higher altitudes than they are at sea level

Temperature  Temperature - the average amount of energy of motion of each particle of a substance –Caused by heat release of friction from molecules banging into each other  Tool to measure-thermometer  Units – o C, o F, K

Heat Transfer  Heat- the transfer of energy from a hotter object to a cooler object  Heat can be transferred in 3 ways –Radiation –Conduction –Convection

Radiation  Radiation- the transfer of energy without objects coming in contact with one another  Example: –The sun heats the Earth

Conduction  Conduction- heat transfer by two objects in direct contact with one another  Examples: –Burning your feet on the hot sand –Pan of food on stove

Convection  Convection-heat transfer through a fluid –Fluids are gases or liquids  Examples: –Boiling water –Heating your home

Effects of Pressure on Your Body  Did your ears ever “pop” when you rode in an elevator or airplane?  As altitude increases, there is less air above you in the column (less mass above you), so the lower the air pressure and the density is lower.  Did your ears ever “pop” when you swam or dove to the bottom of swimming pool? As depth below the surface is increasing, in addition to the column of air above you, there is also a column of water (more mass above you), so the greater the pressure and the density.

 There is pressure inside your ear and elsewhere inside your body.  Since pressure is a force, unbalanced forces cause motion.  If the pressure outside or inside your body is too high or too low, it causes your eardrum to move allowing air to move in or out to equalize the pressure. The Human Ear and Pressure

Altitude Sickness  The higher you climb, the less air there is above you in the column (less mass above you), so the lower the air pressure and the less dense the gas.  D=M V  F=M x A  When you are in an airplane, airlines artificially pressurize the cabins to avoid altitude sickness

Airplanes Issue #1  Propeller airplanes maximum altitude 50,000 feet  Jet planes maximum altitude 120,000 feet  Engines burn fuel  Burning requires oxygen  The amount of oxygen decreases as altitude increases

Airplanes Issue #2  As altitude increases, there is less air above you in the column (less mass above you), so the lower the air pressure and the less dense the gas.  D=M V  F=M x A

High Altitude Training  As altitude increases, there is less air above you in the column (less mass above you), so the lower the air pressure and the density of oxygen is lower.  In order to survive, your body produces more red blood cells over time to use all of the available oxygen in every breath.  By training at such high altitudes the hemoglobin values in the blood become higher, making it possible to intake oxygen more effectively, and physical capabilities increase.  When climbing a mountain, you get out of breath easily because there is less oxygen in each cubic meter of air

Sports at High Altitudes  As altitude increases, there is less air above you in the column (less mass above you), so the lower the air pressure and the density is lower.  The less dense the air the fewer air molecules there are in it. Friction is caused by objects colliding with molecules in the air. Friction opposes the motion of objects. The fewer air molecules there are, the less friction there is, so objects will travel further at high altitude than low altitude.  Sports teams that play their home games at high altitudes (Denver, Colorado) have an advantage because of this and the issues dealing with altitude sickness.

Diving Issues Deep sea diving As depth below the surface is increasing, in addition to the column of air above you, there is also a column of water (more mass above you), so the greater the pressure and the density.  Bends-Too rapid an ascent from great depths causes the diver to suffer decompression sickness  At normal altitudes, nitrogen and other gases are exhaled or dissolved in the blood and tissues.  However, during severe changes in altitude and air pressure, nitrogen and other gases form gas bubbles. These bubbles block the flow of blood.

Diving Issues continued  Much like airplanes are pressurized to avoid altitude sickness, submarines, submersible divers, and scuba air tanks are pressurized.