CLOUD SEEDING
PRECIPITATION
A method during drought
conditions used to produce
precipitation by sprinkling
silver iodide and dry ice into
clouds
Any form of water that falls
from clouds and reaches
Earth’s surface
RAIN
Most common form of
precipitation
SLEET
Raindrops that fall through a
layer of air that is below 0 C
and are smaller than 5mm in
diameter
FREEZING RAIN
Raindrops falling through
cold air near the ground that
freezes on a cold surface
SNOW
Water vapor in a cloud that is
converted directly to ice
crystals
HAIL
Round pellets of ice larger
than 5mm in diameter
formed during thunderstorms
RAIN GAUGE
Open-ended can or tube that
collects rainfall
WINDS
The horizontal movement of
air from an area of high
pressure to an area of low
pressure
ANEMOMETERS
Instrument used to measure
wind speed
TEMPERATURE
The average amount of energy
of motion of each particle in a
substance
CONDUCTION
Heat transfer by objects in
direct contact with each
other
CONVECTION
Heat transfer by the
movement of molecules in a
fluid
RADIATION
Heat transfer without the
objects coming in contact with
each other
WATER CYCLE
The movement of water
between the atmosphere and
Earth’s surface (evaporation,
condensation, &precipitation)
EVAPORATION
Process by which water
molecules in liquid water
escape into the air as water
vapor
HUMIDITY
The measure of the amount of
water vapor in the air
RELATIVE
HUMIDITY
The percentage of water
vapor that is actually in the
air compared to the
maximum amount of water
vapor the air can hold
Instrument used to measure
relative humidity
PSYCHROMETER
FORMATION OF
CLOUDS
When water vapor in the air
condenses to form liquid
water or ice crystals
ISOBARS
Lines joining places on a
weather map that have the
same air pressure
LOCAL WINDS
Winds that blow over short
distances
LAND BREEZE
Local winds that blow from
the land to a body of water
during the night
SEA BREEZE
Local winds that blow from
an ocean or lake to the land
during the day
GLOBAL WINDS
Winds that blow steadily from
specific directions over long
distances
JET STREAMS
Bands of high-speed winds
about 10 km above the
Earth’s surface
AIR MASSES
A huge body of air that has a
similar temperature,
humidity, and air pressure
at any given height
FOUR TYPES OF AIR
MASSES
1.maritime tropical
2.continental tropical
3.maritime polar
4.continental polar
FRONTS
The boundary where two
unlike air masses meet
COLD FRONT
When a fast-moving cold air
mass takes over a warm air
mass producing possible
thunderstorms with heavy
rains or snow
WARM FRONT
A warm air mass takes over
a slow-moving cold air mass,
produces humid, light rain
or snow
STATIONARY
FRONTS
When cold and warm air
masses meet and neither can
move the other
OCCLUDED FRONTS
When a warm air mass is
caught between two cooler air
masses
WEATHER
Condition of Earth’s
atmosphere at a particular
time and place
ATMOSPHERE
The envelope of gases that
surrounds the planet
TOPOSPHERE
Layer where weather occurs
STRATOSPHERE
Layer where the ozone is
located
MESOSPHERE
Layer that protects the
Earth’s surface from being hit
by meteoroids
THERMOSPHERE
The biggest and hottest layer
(Ionosphere and Exosphere
are part of this layer)
IONOSPHERE
Aurora Borealis (Northern
Lights) are seen here
EXOSPHERE
Outermost layer of the
atmosphere
AIR PRESSURE
A force resulting from the
weight of a column of air
pushing down on an area
BAROMETER
Instrument used to measure
air pressure
ALTITUDE
Elevation or distance above
sea level; as altitude
increases, the density of the
air decreases
STORM
A violent disturbance in the
atmosphere
THUNDERSTORM
A small storm with heavy
precipitation, thunder, and
lightning that form in
cumulonimbus clouds
TORNADO
A rapidly whirling, funnelshaped cloud that reaches
down from a storm cloud to
touch Earth’s surface
TORNADO ALLEY
The five states it crosses are:
Texas, Oklahoma, Kansas,
Nebraska, and Iowa
TORNADO WATCH
An announcement that
tornadoes are possible in
your area
TORNADO WARNING
An announcement that a
tornado has been sighted and
you should report to a storm
shelter or the basement of a
building
HURRICANE
A tropical cyclone that has
winds of 119 km/h or higher
STORM SURGE
A “dome” of water that
sweeps across the coast
where a hurricane lands
WINTER STORM
A large amount of humid air
that cools below 0 C can
produce one
METEROLOGIST
A scientist who studies
weather and tries to predict it