Transcript Weather PPT Final

Today’s Weather
is brought to you
by Westly Whithers
Westly Whithers
here to give you the latest about
our weather.
First, you need to know a little about me
and how I make my predictions.
Some call me a
weatherman but I went
to school to learn more
and became a ………
A scientist who studies
and measures weather
conditions.
• Meteorology is the
study of weather.
• Need to know how to use and
read the following instruments:
WIND VANE
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A wind vane shows the direction
the wind is coming from.
Wind often brings a change in
weather…
Letters on the wind vane show
which way is north, south, east,
and west. An arrow turns to point
into the wind. If the arrow points
north, the wind is from the north. It
is a called a north wind. If the
arrow points between two
directions, both directions are used
to tell the wind direction. For
example, the wind could be a
northeast wind.
Say it’s winter. What do you think
a wind blowing from the South
might bring?
ANEMOMETER
• An anemometer measures
the speed of the wind.
• The wind pushes the cups
and makes them spin. The
spinning part of the
anemometer is attached to a
dial that shows how fast the
wind is blowing.
THERMOMETER
 A thermometer is a tool that measures
temperature.
 Temperature can be measured using Celsius (C)
or Fahrenheit (F) scale. Temperature is measured
in degrees.
 The tube thermometer contains a liquid. Heat
causes matter to expand, so the liquid expands
and moves up the tube when the air temperature
gets warmer. The liquid moves down the tube if
the air temperature gets cooler.
 The circle thermometer has pieces of metal inside
that expand as the temperature gets hotter. A
pointer hooked to these metal pieces moves and
points to the temperature.
 A change in temperature is a sign that rain might
fall soon.
HYGROMETER
• A hygrometer measures humidity (moisture)
in the air.
• What do you think an increase in
humidity might mean for the weather?
BAROMETER
• A barometer measures
changes in the air pressure.
• A rising barometer reading which
shows increasing air pressure often
occurs right before colder air arrives.
• Because cold air has less water in it, a
rising barometer also means lower
humidity and less chance of rain.
• What would a falling barometer
reading mean?
RAIN GAUGE
• Instrument that collects and
measures the amount of
precipitation.
• Rain gauges only indicate
rainfall in a localized area.
• The rain can be measured in
centimeters or inches
Satellite
• A device sent to space to take pictures of
the Earth’s weather and relay them back
to Earth.
Can you name the weather
instrument?
What does it do?
Weather Vane
Weather Vane
finds the wind’s direction
Can you name this weather
instrument?
What does
it do?
Anemometer
measures wind speed
Can you name this weather
instrument?
What does
it do?
Rain Gauge
measures the
amount of liquid
precipitation
over a period
of time.
Can you name this weather
instrument?
What does
it do?
Thermometer
measures air temperature
Can you name this weather
instrument?
What does
it do?
Barometer
measures pressure of the atmosphere (air pressure)
hygrometer
satellite
Weather vs. Climate
Weather
Climate
Air Masses
• Air moves in large air massesan air mass is a large body of air that has the same
temperature and humidity throughout.
• Air masses can be warm or cold, humid or dry
• An air mass takes on the characteristics of the region
that it forms over
• What would an air mass be like that formed over the
equator? Northern Canada?
• There are four air masses that affect our weather- they
usually move from west to east
• When the weather changes in a location, what do you
think happens to the air mass?
Fronts
• The border where two air masses meet is
called a front
• Most weather changes occur along fronts
• There are two main types of fronts:
cold and warm
Fronts
• A cold front forms where a cold air mass moves
over a warm air mass- the warm air mass is pushed
up and cooled- when this happens, the water vapor in
the air mass condenses quickly and can cause brief
heavy rain, thunderstorms, or snow.
• A warm front forms where a warm air mass moves
over a cold air mass- as the warm air slides over,
stratus clouds form ahead of the front and can cause long
lasting rain or snow storms.
Weather Maps
• A weather map gives information about
what the weather is like in an area
Weather Map Symbols
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A sun or rain symbol shows the current weather in the area
Weather fronts are shown by red and blue lines
Temperatures can be written on a map or shown using color
High and low pressure systems are shown with the letters
“H” and “L”
• A high pressure system is formed where an area of cool
dense air is surrounded by lower pressure air
• A low pressure system forms where an area of warm light air
is surrounded by higher pressure air
• Other things a weather map can show include high and low
temperatures and wind speed and direction
Weather Map Symbols
A map’s
key will tell
you what
each symbol
means.
Weather Map #1
Weather Map #2
Weather Map #3
Weather Map #4