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Grade 4 D-1 Sci. Def
Chapter 1 Weather Conditions
Term | Definition |
---|---|
Atmosphere | The layer of air that surrounds our planet |
Air pressure | Particles of air pressing down on the Earth's surface |
Troposphere | The layer of atmosphere closest to Earth |
Stratosphere | The layer of atmosphere that contains ozone and is located above the troposphere |
Greenhouse effect | The warming of Earth caused by the atmosphere trapping thermal energy from the sun |
air mass | A huge body of air which all has similar temperature and moisture |
Front | The border where two air masses meet |
cirrus | Wispy, high-altitude clouds that are made up of ice crystals |
Cumulus | Puffy cotton-ball clouds that begin to form when water droplets condense at middle altitudes |
Cumulonimbus | Towering, dark rain clouds with a nimbus, or halo, of gray-white. |
Stratus | Dark gray clouds that form a low layer and sometimes bring light rain or snow showers |
Barometer | An instrument that measures air pressure |
Humidity | The amount of water vapor in the air |
Hygrometer | A tool to measure moisture in the air |