Air
the invisible mixture of gases surrounding the Earth
Air Pressure
the force with which air presses against surfaces
Atmosphere
the blanket of gases surrounding the Earth, including the air we breathe
Forecast
a statement about what the weather should be like during the next few days
Isobar
a line on a weather map connecting places of equal air pressure
Meteorologist
a scientist who studies the Earth's atmosphere to report and predict the weather
Molecules
a small particle made up of two or more atoms
Vapor
water in the form of gas
Weather
the local condition of the atmosphere, such as hot, rainy, windy, or stormy
Meteorology
the discipline dealing with the Earth's air, especially the movements and events that cause weather
Barometer
an instrument which measures air pressure at a particular location
Millibar
a unit by which air pressure is measured
Aneroid Barometer
a small modern barometer which measures changes in air pressure, causing a pointer to move along a scale
Air Mass
a large body of air in the atmosphere that has about the same humidity and temperature
Dew Point
the temperature at which water vapor turns into water droplets
Evaporation
the process by which a liquid is changed into a vapor or gas
Humidity
the amount of water vapor in the air
Precipitation
moisture condensed from vapor by cooling, such as dew, rain, hail, or snow
Cirrus
a thin, high, featherlike cloud forming very high in the atmosphere
Convection
the upward movement of air caused by heat from the Earth; the air cools as it rises, then sinks back toward Earth
Front
the boundary between two air masses
Stratus
a flat, sheetlike rain cloud spreading over the sky
Cumulonimbus
a rain-producing cloud with an anvil-shaped top
Cumulus
a fair-weather cloud rounded on the top and flat on the bottom
Isotherm
a line on a weather map connecting places having the same temperature
Lightning
discharge of electricity between clouds or between clouds and the ground, seen as a flash of light
Thunder
a loud noise caused by lightning expanding and contracting the air