Weather SOL 4.6

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 the Earth’s atmosphere closest to Earth

stratosphere the layer of the Earth’s atmosphere containing most of the atmosphere’s ozone

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 the middle altitudes

cumulonimbus towering, dark rain clouds with nimbus, or halo, of gray-white

stratus dark gray clouds that form a low layer and sometimes bring light rain or snow shower

barometer measures air pressure

humidity amount of water vapor in the air

hygrometer Instrument that measures humidity