Download Weather Instruments

Weather Instruments
FOSS/DSM
1
Weather Instruments
Objective:
After copying notes, students will be
able to identify and classify the
different types of weather instruments
and their uses through hands on
exploration and by analyzing written
and oral text by the end of the lesson.
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NJCSS: 5.4F CPI 01 Identify patterns in data collected from basic weather instruments
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Weather Instruments
Essential Questions:
What are weather
instruments and how are they
used?
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Weather Instruments
Meteorologist use different tools to
measure weather. Here are some of
the instruments they use:
– Thermometer
– Barometer
– Anemometer
– Hygrometer
– Rain gauge
– Wind Vane
– Weather balloon
– Satellite
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Thermometer
A thermometer measures
heat and cold. Meteorologist
use it to measure air
temperature. Liquids expand
(get bigger) when heated and
contract (get smaller) when
cooled. That means their
volume (occupied space)
changes with their
temperature.
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Thermometer
The liquid inside older thermometers is
mercury. It was used because of its
resistance to heat and cold. Unlike
water, mercury freezes at minus 39
degrees Celsius (-39°C) and boils at
three hundred fifty seven degrees
Celsius (357°C).
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Thermometer
Units of Measure
The two (2) measurement units used with a
thermometer are degrees Fahrenheit and
degrees Celsius.
The Fahrenheit scale
sets the freezing point
of water at 32 degrees
(32°F) and the boiling
point at 212 degrees
(212°F).
The Celsius scale sets
the freezing point of
water at 0 degrees
(0°C) and the boiling
point at 100 degrees
(100°C).
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Barometer
A barometer measures air
pressure or barometric
pressure. The barometer
dial is marked in two
scales. The outer scale
shows the units of inches
of mercury. The inner
scale shows air pressure
in millibars.
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Air Pressure
Air pressure is a function of the
quantity of air and the amount of
space in which the air is contained.
Air pressure is also the function of
temperature.
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Air Pressure and Weather
Changing air pressure indicates changing
weather.
Rising air pressure usually means that
cooler, drier air is coming, so there will be
fair weather.
Falling air pressure usually means that
warmer, moister air is coming, so there will
be wet weather.
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Anemometer
An anemometer
measures the speed
or strength of wind.
The most common
types of anemometer
have a mechanism that
rotates as it catches the
wind.
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Wind Speed and Weather
Wind speed is related directly to wind
strength. Wind strength is commonly
reported on the Beaufort scale. The
Beaufort scale rates the strength of wind on
a scale of 0 – 12.
A Beaufort number of 0 indicates total calm.
A Beaufort number of 12 indicates hurricane
strength winds (exceeding 74 mph).
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Hygrometer
A hygrometer measures
relative humidity. Humidity is
the amount of water vapor in the
air.
A reading of 100 percent relative
humidity means that the air is
totally saturated with water vapor
and cannot hold any more,
creating the possibility of rain.
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People and Humidity
The process of sweating is the human body's
attempt to keep cool and maintain its current
temperature. If the air is at 100-percent relative
humidity, sweat will not evaporate into the air. As
a result, we feel much hotter than the actual
temperature when the relative humidity is high. If
the relative humidity is low, we can feel much
cooler than the actual temperature because our
sweat evaporates easily, cooling us off.
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Rain Gauge
A rain gauge is an instrument used to
gather and measure the amount of
liquid precipitation over a set period of
time. Most standard rain gauges have
a wide funnel leading into a cylinder
that is marked in inches or centimeters.
They are calibrated (set up) so that
one-tenth of an inch of rain measures
one inch when it collects inside. In
other words, each inch in the funnel
counts as one-tenth of an inch of rain.
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Wind Vane
A wind vane indicates in what direction the
wind is traveling.
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Weather Balloon
• A Weather balloon is a mobile weather
station sent up to measure atmospheric
pressures, temperature, wind speeds and
humidity.
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Satellite
• Weather satellites are used for viewing
large weather systems on Earth such as
hurricanes and other cloud formations.
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