CONDENSATIONThe process by which a gas changes to a liquidCONDUCTIONthe direct transfer of heat from one substance to another substance that it is touchingCONTINENTAL AIR MASSA dry air mass that forms over landCONVECTIONthe transfer of heat by the movement of a fluidCORIOLIS EFFECTTHE WAY THE EARTH'S ROTATION MAKES WINDS IN THE NORTHERN HEMISPHERE CURVE TO THE RIGHT AND WINDS IN THE SOUTHERN HEMISPHERE CURVE TO THE LEFTCUMULUSClouds that form less than 2 kilometers above the ground and look like fluffy, rounded piles of cotton.CYCLONEa swirling center of low air pressureDENSITYthe amount of mass in a given volumeDEW POINTthe temperature at which condensation beginsEL NINOthe name given to the periodic warming of the ocean that occurs in the central and Eastern Pacific; A major El Nino episode can cause extreme weather in many parts of the worldELECTROMAGNETIC WAVEa form of energy that can travel through spaceEVACUATEto move away temporarilyEVAPORATIONthe process by which water molecules in liquid water escape into the air as water vaporEXOSPHEREThe outer layer of the thermosphere, extending outward into space.FLASH FLOODA sudden, violent flood that occurs within a few hours, or even minutes, of a heavy rainstormFRONTthe area where air masses meet and do not mixGLOBAL WINDwinds that blow steadily from specific directions over long distancesGREENHOUSE EFFECTThe process by which heat is trapped in the atmosphere by water vapor, carbon dioxide, methane, and other gases that form a "blanket" around Earth.HEATmovement of thermal energy from a substance at a higher temperature to a substance at a lower temperatureHUMIDITYa measure of the amount of water vapor in the airHURRICANEa tropical storm that has winds of about 119 kilometers per hour or higherINFRARED RADIATIONa form of energy with wavelengths that are longer than visible lightIONOSPHEREthe lower part of the thermosphere, where electrically charged particles called ions are foundISOBARa line on a weather map that joins places that have the same air pressureISOTHERMline drawn on a weather map that connects points having equal temperatureJET STREAMbands of high-speed winds about 10 kilometers above Earth's surfaceLAND BREEZEthe flow of air from land to a body of waterLATITUDEdistance north or south of the Equator, measured in degrees.LIGHTNINGa sudden spark, or energy discharge, caused when electrical charges jump between parts of a cloud, between nearby clouds, or between a cloud and the groundLOCAL WINDWinds that blow over short distances.MARITIMEa humid air mass that forms over oceansMERCURY BAROMETERAn instrument that measures changes in air pressure, consisting of a glass tube partially filled with mercury, with its open end resting in a dish of mercury. Air pressure pushing on the mercury in the dish forces the mercury in the tube to be higher.MESOSPHEREThe middle layer of Earth's atmosphere; the layer in which most meteoroids burn up.METEOROLOGISTScientists who study the causes of weather and try to predict it.OCCLUDEDCut off, as the warm air mass at an occluded front is cut off from the ground by cooler air beneath itOZONEa form of oxygen that has three oxygen atoms in each molecule instead of two. protects us from dangerous ultraviolet radiation from the sunPHOTOCHEMICAL SMOGa brownish haze that is a mixture of ozone and other chemicals, formed when nitrogen oxides, hydrocarbons, and other pollutants react with each other in the presence of sunlightPOLARa cold air mass that forms north of 50 degrees north latitude or south 50 degrees south latitude and has high air pressurePOLLUTANTa harmful substance in the air, water, or soilPRECIPITATIONany form of water that falls from clouds and reaches Earth's surfacePRESSUREthe force pushing on an area or surfacePSYCHROMETERAn instrument used to measure relative humidity, consisting of a wet-bulb thermometer and a dry-bulb thermometer.RADIATIONthe direct transfer of energy by electromagnetic wavesRELATIVE HUMIDITYthe percentage of water vapor in the air compared to the maximum amount the air could holdSCATTERINGreflection of light in all directionsSEA BREEZEthe flow of cooler air from over an ocean or lake toward landSTORMa violent disturbance in the atmosphereSTORM SURGEA "dome" of water that sweeps across the coast where a hurricane lands.STRATOSPHEREThe second-lowest layer of Earth's atmosphere; the ozone layer is located in the upper stratosphere.STRATUSclouds that form in flat layersTEMPERATUREA measure of the average energy of random motion of the particles in a substanceTHERMOSPHEREThe outermost layer of Earth's atmosphere.TORNADOA rapidly whirling, funnel-shaped cloud that reaches down from a storm cloud to touch Earth's surface, usually leaving a destructive pathTROPICALa warm air mass that forms in the tropics and has low air pressureTROPOSPHEREthe lowest layer of earth's atmosphere, where weather occursULTRAVIOLET RADIATIONa form of energy with wavelengths that are shorter than visible lightWATER VAPORWater in the form of a gasWEATHERthe condition of Earth's atmosphere at a particular time and placeWINDthe horizontal movement of air from an area of high pressure to an area of lower pressureWIND CHILL FACTORincreased cooling caused by the wind
