The layer of air that surrounds our planet

atmosphere

Particles of air pressing down on the Earth’s surface

air pressure

The layer of the
Earth’s atmosphere that is closest to the Earth

troposphere

The layer of the
Earth’s atmosphere that contains the ozone

stratosphere

The warming of the
Earth caused by the atmosphere trapping thermal energy from the
Sun

Greenhouse effect

A huge body of air that has similar temperature and moisture

Air mass

The border where two air masses meet

Front

Wispy , high-altitude clouds that are made up of ice crystals
*fair weather

cirrus

Puffy cotton-ball clouds that form when water droplets condense at middle altitudes

cumulus

Towering dark rain clouds with a nimbus, or halo, of gray-white
*thunderstorms, rain

cumulonimbus

Dark gray clouds that form a low layer and sometimes brings light rain or snow showers
*blanket

stratus

Instrument that measures air pressure

barometer

The amount of water vapor in the air

Humidity

An instrument that measures moisture in the air

hygrometer

An instrument that is used to measure wind speed .

anemometer