7.4 FORECASTING THE WEATHER - INSTRUMENTS
TN Standard: I can analyze meteorological data to predict weather conditions.
THINK ABOUT IT…
If you did not have the benefit of the weather forecast on the news, radio,
TV or the internet…
How would you forecast the weather?
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How Do They Do It?
A meteorologist is a person who observes and collects data on atmospheric conditions to make weather
predictions.
Meteorologists generate a weather forecast, which is a prediction of weather conditions over the next
5-7 days.
Where do meteorologists get their information?
Today you will learn how instruments along with technology are used to create weather forecasts.
Meteorologists measure various atmospheric conditions: Can you name some from our collection of
weather data?
Be a “Meteorologist” to your partner and list as many as you can think of on the Post-It notes at your
table!
High in the Sky
WEATHER BALLOONS carry electronic equipment that can measure weather conditions as high as 30 km
(18 miles) above Earth’s surface. They’re launched twice daily.
They carry equipment that measures:
temperature
air pressure
relative humidity
wind speed
direction of the wind
They carry radio transmitters that send measurements around the world.
Measuring Air Temperature
What do your parents use to measure your temperature?
How does a thermometer work?
Thermometer
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Measuring Air Pressure
A BAROMETER is used to measure air pressure sometimes called barometric pressure.
Remember:
31–32 = fair, pretty days
30 = weather starts changing
PRESSURE’S HIGH – CLEARS THE SKY
PRESSURE’S LOW – STORMS WILL BLOW
28-29 = rain to stormy
Measuring Wind Direction:
Windsock
How do you think a windsock works?
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Why is a windsock often seen at airports?
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Wind vane (a.k.a.. weather vane)
Have you ever seen a weather vane up on a roof of a barn or house? ___________________________
Why do you think they are placed there?
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How do you think a wind vane works?
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Measuring Wind Speed
An instrument used to measure wind speed is called an ANEMOMETER.
It consists of 3-4 cups connected by spokes to a pole.
Radar
RADAR is used to find the location, movement, amount, and form of precipitation.
Doppler Radar – used to track precipitation. What technology does radar use?
Doppler Effect
It is a specialized radar that makes use of the Doppler Effect to produce velocity data about objects at a
distance. It beams a microwave signal towards a desired target, listens for its reflection, then analyzes
how the frequency of the returned signal has been altered by the object’s motion.
Bats use the Doppler Effect to locate prey and to navigate. Bats emit high-frequency sounds that
bounce off objects. If the objects are moving, then the wave frequency changes. If the frequency does
not change, then the bat knows the object is stationary.
Weather Satellites
Orbit the Earth
Provide images of weather systems that are featured on the weather reports, tracks storms,
measures humidity, wind speeds, temperatures at different altitudes.
In 1735, Ben Franklin said, “Some people are weatherwise, but most are otherwise.”
With all the technology available to us today, forecasting the weather is relatively easy for anyone to
access. We’re more familiar with the tools and concepts of weather forecasting.
Weather plays an important role in your life and well as the lives of others.
PUTTING IT TOGETHER
Identify each weather instrument again and describe what it measures on a separate piece of paper.