• Air – a mixture of gases. 78% Nitrogen, 20% Oxygen, 2% All other gases combined


    Air Mass – a large body of air with the same temperature and moisture throughout.


    Air Pressure – the weight of all the air above pushing down.


    Anemometer – the instrument that measures wind speed.


    Atmosphere – the thin layer of gases that surround Earth.


    Barometer – the instrument that measures air pressure.


    Climate – the condition of the atmosphere over a long period of time.


    Cloud – a collection of billions of droplets of liquid water in the sky.


    Cold Front – cold air pushing warm air ahead of it.  Usually brings brief bad weather.


    Condensation – water vapor changing into liquid water as the atoms lose energy.


    Convection – the cyclic motion of liquids and gases due to density differences caused by unequal heating.


    Continental Air Mass – dry air


    Dew Point Temperature – the temperature that water condenses at and forms clouds.


    Evaporation - liquid water changing into water vapor as the atoms gain energy.


    Freezing – liquid water changing into solid water as atoms lose energy.


    Front – the boundary between two air masses.


    Greenhouse Effect – a average increase in air temperature as energy is trapped by greenhouse gases in the atmosphere or the glass in an actual greenhouse.


    Greenhouse Gas – carbon dioxide(CO2), water vapor(H2O) or methane(CH3) trap heat energy in the atmosphere.


    Hazardous Weather – severe storms that are dangerous to people and property, includes thunderstorms, winter storms, tornadoes & hurricanes.


    High Pressure System – cool, dry, dense air that is sinking and produces clear skies and fair weather.

    Humidity – the amount of water vapor in the air.


    Hydrosphere – water layer of Earth


    Jet Stream – air flow in upper atmosphere the influences weather patterns.


    Lithosphere – solid layers of Earth.


    Low Pressure System – warm, moist, light air that rises forming clouds and foul weather.


    Maritime Air Mass – moist air


    Melting – solid water changing to liquid water as the atoms gain energy


    Meteorology – the study of Earth’s atmosphere, weather and climate


    Ozone – a kind of oxygen (O3) in the stratosphere that absorbs and protects you from ultra-violet (UV) radiation


    Polar Air Mass – cold air


    Precipitation – liquid or solid water falling from clouds.


    Prevailing Wind – the usual wind pattern for a latitude zone that controls the direction weather moves.


    Stratosphere – atmosphere layer above troposphere that contains ozone and where the jet stream is.


    Temperature –the average kinetic energy (motion) of particles (a measure of heat energy).


    Transpiration – water vapor moving into the atmosphere from plants


    Tropical Air Mass – warm air


    Troposphere – the lowest atmosphere layer contains water and is where our weather is found. 


    Warm Front - warm air pushing or riding up over cooler air ahead of it.  Usually brings long periods of cloudy or rainy weather.


    Water Cycle – a model used to show the water moving to and from the hydrosphere,  the atmosphere and the lithosphere.


    Weather – the condition of the atmosphere for a short time at a particular place.


    Wind – air moving because of convection and density differences in the atmosphere.