Transcript Precipitation - Laconia School District

Precipitation
Nicole Lavigne
11/30/07
T-3
Vocabulary
• Precipitation: is any form of water that falls from clouds and reaches
earth’s surface.
• Rain gauge: is an open-ended can or tube that collects rainfall.
• Droughts: can cause great hardship
• Common types of precipitation include rain, sleet, freezing rain, hail,
and snow: In warm parts of the world, precipitation is almost always
rain or drizzle. In colder regions, precipitation may fall as snow or
ice.
• Rain is measured with a rain gauge- The amount of rain fall is
measured by dipping a ruler into the water or by reading a marked
scale.
• Scientists have used cloud seeding to produce rain and to clear fog
from airports- Dry ice is sprinkled into the fog, causing ice crystals to
form. This removes some of the fog so pilots can see the runway.
Unfortunately, cloud seeding clears only cold fog, so it’s used for this
purpose is limited.
A rain gauge
Five common types of rain
•
•
•
•
•
Rain: the most common kind of
precipitation is rain.
Sleet: sometimes raindrops fall
though a layer of air below 0c, the
freezing point of water.
Freezing Rain: at other times
raindrops falling though cold air
near the ground do not freeze in
the air.
Hail: round pellets of ice larger
than 5 millimeters in diameter are
called hailstones. Hail forms only
inside cumulonimbus clouds
during thunder storms. A hail
stone starts as an ice pellet inside
a cold region of a cloud.
Snow: often water vapor in a cloud
is converted cloud directly into ice
crystals called snowflakes.
Measuring/ controlling precipitation
• Measuring
precipitation:
meteorologists
measure rainfall with
a rain gauge. A rain
gauge is an openended can or tube
that collects rainfall.
• Controlling
precipitation: In some
regions there maybe
periods that are much
drier than usual. Long
period of unusually
low precipitation are
called droughts can
cause grant hard
ship.
How do hail storms form?
• Hail only forms inside cumulonimbus
clouds during thunder storms.