Transcript Document

Notes on Weather
A. Weather is the short term condition of the
atmosphere over a small area.
B. Weather is described by its conditions, or variables
that change every day.
1. temperature - indicates the amount of heat
in the atmosphere and is measured with a
thermometer
2. Air pressure- air has mass; it is the force that
presses down on earth
a. Caused mainly by changes in
temperature and altitude.
b. The force is measured with a
barometer in either inches
of mercury or
millibars
3. Humidity - the amount of water vapor in the
air
a. Warm air absorbs more water vapor
than cool air; so air temperature
determines how much water vapor can
be absorbed
b. Relative humidity - a comparison of
the actual amount of water vapor in the
air with the maximum amount the air
could absorb at that temperature
1. psychrometer - instrument
used to measure relative
humidity; a wet and dry bulb
thermometer is one type
4. Wind - the horizontal movement of air over
the Earth’s surface
a. Wind speed - a measure of how
fast the air is moving, in miles or
kilometers per hour
1. anemometer - instrument
used to measure wind speed
b. Wind direction - the direction from
which the wind is coming
1. weather vane or wind sock instrument used to determine
wind direction
5. Precipitation - water, in any form that falls from
the atmosphere
a. Temperature determines the type of
precipitation produced
b. Types:
1. Rain - most common
2. Sleet - rain that falls through
a layer of air below freezing; smaller than
5mm
3. Hail - ice larger than 5mm;
updrafts push small ice pellets to higher
parts of the cloud where a new layer of
ice may form; when too heavy it falls
4. Snow - water vapor in a cloud
that form ice crystals
c. Rain Gauge - instrument used to
measure the amount of precipitation in inches
Notes on Clouds
A. Clouds
1. Clouds are millions of tiny droplets of water or ice
crystals
2. Clouds form:
a. When condensation occurs
b. Temperature at which condensation occurs is the
dew point.
c. Water vapor condenses around small particles such
as dust (soil) salt, smoke
d. Water vapor that condenses on grass or on your car
is called dew.
3. Cloud Types- clouds are described by height and
shape
a. Height
1. Cirro – high clouds
2. Alto – middle clouds
3. Strato – low clouds
b. Shape
1. Cirrus – have a feathery look
2. Cumulus – means “heap” or “mass”
3. Stratus – means spread out
c. Fog – clouds that form near the ground
d. Nimbus – means rain
CLOUDS
Notes on Weather
A. ___________ is the short term condition of the
atmosphere over a small area.
B. Weather is described by its conditions, or variables
that change every day.
1. ______________ - indicates the amount of heat
in the atmosphere and is measured with a
______________
2. _____________ - air has mass; it is the force that
presses down on earth
a. Caused mainly by changes in
temperature and altitude.
b. The force is measured with a
________________ in either inches
of _____________ or
________________
4. _________________ - the horizontal
movement of air over the Earth’s surface
a. _______________ - a measure of how
fast the air is moving, in miles or
kilometers per hour
1. ________________ - instrument
used to measure wind speed
b. ______________ - the direction from
which the wind is coming
1. _______________ - instrument
used to determine wind direction
3. ________________ - the amount of water
vapor in the air
a. Warm air absorbs more water vapor
than cool air; so air temperature
determines how much water vapor can
be absorbed
b. ________________- a comparison of
the actual amount of water vapor in the
air with the maximum amount the air
could absorb at that temperature
1. ________________ - instrument
used to measure relative
humidity; a wet and dry bulb
thermometer is one type
5. ________________ - water, in any form that falls from
the atmosphere
a. Temperature determines the type of
precipitation produced
b. Types:
1. ___________ - most common
2. ___________ - rain that falls through
a layer of air below freezing; smaller than
5mm
3. ___________ - ice larger than 5mm;
updrafts push small ice pellets to higher
parts of the cloud where a new layer of
ice may form; when too heavy it falls
4. ___________ - water vapor in a cloud
that form ice crystals
c. ________________ - instrument used to
measure the amount of precipitation in inches