Unit 3 Lesson 3 How Do We Measure Weather?
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Unit 3 Lesson 3 How Do We Measure Weather?
Florida Benchmarks
• SC.5.E.7.3 Recognize how air temperature,
barometric pressure, humidity, wind speed and
direction, and precipitation determine the weather
in a particular place and time.
• SC.5.E.7.4 Distinguish among the various forms
of precipitation (rain, snow, sleet, and hail),
making connections to the weather in a particular
place and time.
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Unit 3 Lesson 3 How Do We Measure Weather?
What’s the Weather Like?
• Weather is what the atmosphere is like at a given
time and place.
• Meteorologists are scientists who study weather.
• Factors such as air temperature, amount of cloud
cover, and amount of precipitation are used to
create weather reports.
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Unit 3 Lesson 3 How Do We Measure Weather?
What’s the Weather Like?
• Weather reports can help you plan your day.
• Airports use weather reports to plan flight
schedules.
• Farmers use weather reports to help care for their
crops.
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Unit 3 Lesson 3 How Do We Measure Weather?
Watching the Weather
• Weather balloons are used to carry weather tools
high into the atmosphere.
• A wind vane measures wind direction by pointing
in the direction from which the wind blows.
• An anemometer measures wind speed. Wind
speed is measured in kilometers per hour.
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Unit 3 Lesson 3 How Do We Measure Weather?
Watching the Weather
• A barometer measures air pressure.
• A hygrometer measures the amount of water
vapor, or humidity, in the air.
• Relative humidity is a percentage. It tells the
amount of water vapor in the air compared to
what the air can hold at a given temperature.
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Unit 3 Lesson 3 How Do We Measure Weather?
Lying Low, Reaching High
• Shape and height are used to classify clouds.
• Stratus clouds form flat layers that cover most of
the sky.
• Cirrus clouds are thin, white, and feathery.
• Cumulus clouds are puffy and white.
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Unit 3 Lesson 3 How Do We Measure Weather?
Lying Low, Reaching High
• Low clouds form below about 2,000 m (6,500 ft).
• Middle clouds form between 2,000 m and 6,000 m
(6,500 ft and 20,000 ft).
• High clouds form above 6,000 m (20,000 ft). High
clouds are often made of ice crystals because of
the low temperatures.
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Unit 3 Lesson 3 How Do We Measure Weather?
Lying Low, Reaching High
• Use this cloud classification chart to identify the
clouds in the sky today.
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Unit 3 Lesson 3 How Do We Measure Weather?
It’s Pouring Solids and Liquids
• Precipitation is solid or liquid water that falls from
clouds to Earth’s surface.
• As air temperature changes, precipitation may fall
as either a solid or liquid.
• Air temperature changes by season, elevation,
and location.
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Unit 3 Lesson 3 How Do We Measure Weather?
It’s Pouring Solids and Liquids
• Rain is liquid and falls through warm or cool air.
• Snow is solid and falls through cold air.
• Sleet is precipitation that freezes near the ground.
• Hail is solid precipitation made of layers of ice.
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Unit 3 Lesson 3 How Do We Measure Weather?
Rain
• Rain can start out high in the atmosphere as
snow.
• Raindrops can range in size from about 0.1 mm in
diameter to as large as 6 mm in diameter.
• Rain gauges are used to measure the depth of
rain that falls in an area.
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Unit 3 Lesson 3 How Do We Measure Weather?
Sleet
• Sleet is made up of small pellets of ice.
• Sleet can form when snow partially melts as it
falls through a warm layer of air.
• The melted snow can freeze again in a cold layer
near the ground to form sleet.
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Unit 3 Lesson 3 How Do We Measure Weather?
Hail
• Hail forms when wind carries raindrops high into
the colder part of a cloud.
• The raindrops freeze and fall to a warmer part of a
cloud.
• A new layer of moisture may stick to the hail
particles.
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Unit 3 Lesson 3 How Do We Measure Weather?
Hail
• The wind can carry the hail particles up again and
again.
• Large hail particles will fall to the ground.
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Unit 3 Lesson 3 How Do We Measure Weather?
Snow
• Snow forms when water vapor turns directly into a
solid in the atmosphere.
• Air currents keep snow crystals in the
atmosphere.
• Once a snow crystal is too large, it will fall to
Earth.
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