# Describing Weather

```Lesson 1 | Describing Weather
Student Labs and Activities
Page
8
Content Vocabulary
9
Lesson Outline
10
MiniLab
12
Content Practice A
13
Content Practice B
14
School to Home
15
Key Concept Builders
16
Enrichment
20
Challenge
21
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Launch Lab
Weather
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Name
Date
Launch Lab
Class
LESSON 1: 15 minutes
Can you make clouds in a bag?
When water vapor in the atmosphere cools, it condenses. The resulting water droplets make
up clouds.
Procedure
1. Read and complete a lab safety form.
2. Half-fill a 500-mL beaker with ice
and cold water.
4. Carefully lower the bag into the ice
water. Record your observations in
3. Pour 125 mL of warm water into a
resealable sandwich bag and seal
the bag.
1. What did you observe when the warm water in the bag was put into the beaker?
2. What explanation can you give for what happened?
Key Concept What could you see in the natural world that results from the same
process?
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Weather
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3.
Name
Date
Class
Content Vocabulary
LESSON 1
Describing Weather
Directions: Write the correct term in the boxes to the right of each definition. Then unscramble the letters in the
shaded boxes to spell a ninth term.
air pressure
dew point
humidity
kinetic energy
relative humidity
variable
water cycle
weather
precipitation
1. series of processes through which
water moves around the globe
2. the amount of water vapor in the air
compared to the maximum possible
amount of water vapor the air can
contain at that temperature
3. energy an object has because of its
motion
4. atmospheric conditions at a certain
place and time
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5. a quantity that can be changed
6. a force exerted by a column of air
7. the amount of water vapor in the air
8. boundary at which water vapor
becomes liquid water
9. When they are unscrambled, the letters from the shaded boxes spell
, which includes rain, snow, and sleet.
Weather
9
Name
Date
Class
Lesson Outline
LESSON 1
Describing Weather
A. What is weather?
1. The atmospheric conditions, along with short-term changes, make up the
of a certain place at a certain time.
B. Weather Variables
1. Scientists who study and predict weather are
2. Air
.
is the measure of the average kinetic energy of
molecules in the air. Molecules in warm air move
molecules in cooler air.
3.
than
is the pressure that a column of air exerts on the air or
surface below it.
a. Air pressure decreases as altitude
b. A(n)
4.
.
is an instrument used to measure air pressure.
is caused by air moving from an area of high pressure
to an area of low pressure.
a. In a south wind, the wind is coming from the
.
.
5. The amount of water vapor in the air is
a. When air is
.
, it holds the maximum amount of water
vapor possible at that
b.
.
is the amount of water vapor in the air compared to
the maximum amount of water vapor the air can hold at that temperature.
c. Relative humidity is reported as a(n)
.
6. When air near the ground becomes saturated, the water vapor condenses into a
liquid and forms
.
a. If the temperature is below 0°C, ice crystals, referred to as
, form.
b. The temperature at which air becomes fully saturated because the
temperature decreases while the amount of moisture stays constant is
the
10
.
Weather
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b. The instrument used to measure wind speed is a(n)
Name
Date
Class
Lesson Outline continued
7. As warm air rises in the atmosphere, it
.
a. When the air cools enough that the
is reached, small
droplets of water form.
b.
are water droplets or ice crystals suspended in the
atmosphere.
c.
is a cloud that forms near Earth’s surface.
d.
clouds are flat, white, and layered.
e.
clouds are fluffy and are present at 2,000 to 6,000 m
altitude.
f.
clouds are wispy and are present above 6,000 m
altitude.
8.
is water, in liquid or solid form, that falls from the
atmosphere.
a. Precipitation that falls as liquid water is
.
b. Precipitation that is solid crystals of ice is
.
c. Precipitation that starts as snow and then melts and freezes again is
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
called
d.
.
is precipitation formed when ice pellets rise and fall
within a cloud, adding new layers of ice during each cycle.
9. The
is the series of natural processes in which water
continually moves among oceans, land, and the atmosphere.
a. Water enters the atmosphere as water vapor when liquid water on Earth’s
surface
b. As water vapor cools, it
c. Clouds produce
.
, forming liquid water.
, which is when liquid or frozen
water falls to Earth’s surface.
Weather
11
Name
Date
MiniLab
Class
LESSON 1: 20 minutes
When will dew form?
The relative humidity on a summer day is 80 percent. The temperature is 35°C. You want to
find out if the dew point will be reached if the temperature drops to 25°C later that
evening. Use the figure below to find the amount of water vapor needed for saturation at
each temperature.
Maximum Water Vapor in Air
Water vapor in air (g/m3)
7
6
5
4
3
2
1
0
0
5
10 15 20 25 30 35 40 45
Temperature (°C)
1. Calculate the amount of water vapor in
air that is 35°C at 80 percent relative
humidity. (Hint: multiply the amount
of water vapor air can contain at 35°C
by the percent of relative humidity.)
2. At 25°C, air can hold 2.2 g/cm3 of
water vapor. If your answer from step
1 is less than 2.2 g/cm3, the dew point
is not reached and dew will not form.
If the number is greater, dew will form.
Analyze and Conclude
Key Concept After the Sun rises in the morning, the air’s temperature increases.
How does the relative humidity change after sunrise? What does the line represent?
12
Weather
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Procedure
Name
Date
Class
Content Practice A
LESSON 1
Describing Weather
Rain
Cloud
droplets
Warm
Raindrops
Snow
Ice
Cloud
crystals droplets
Cold
Snowflakes
Sleet
Ice
crystals
Hail
Cloud
droplets
Cloud
droplet
Warm
Raindrops
Hail
Cold
Warm
Ice
crystal
Warm
Cold
Directions: Use the diagram to answer each question.
Question
Rain
Snow
Sleet
Hail
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What form is the water in
when it is in the clouds—
liquid or solid?
What is the air temperature
near the clouds—warm or
cold?
What is the air temperature
near Earth’s surface—warm
or cold?
What is the form of
precipitation that falls—
liquid or solid?
How are rain, snow, sleet,
and hail part of the water
cycle?
What role does temperature
play in the type of
precipitation that develops?
Weather
13
Name
Date
Content Practice B
Class
LESSON 1
Describing Weather
Directions: Explain how each variable contributes to weather in the space provided.
1.
Air pressure
2.
Wind
3.
Humidity
4.
Relative humidity
5.
Dew point
6.
Clouds
7.
Fog
8.
Precipitation
9.
Variables within
the water cycle
10.
Evaporation in
the water cycle
11.
Condensation in
the water cycle
12.
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Air temperature
Weather
Name
Date
School to Home
Class
LESSON 1
Describing Weather
Directions: Use your textbook to answer each question.
1. Weather is the atmospheric conditions (and the short-term changes in
those conditions) of a certain place at a certain time.
What variables do meteorologists use to describe weather?
2. Air pressure is the pressure that a column of air exerts on the air or
surface below it.
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What tool is used to measure air pressure?
3. When there is high humidity, there is a large amount of water vapor in the air.
What is the difference between humidity and relative humidity?
4. Water vapor can condense in the air, creating clouds and fog.
How are clouds and fog related to precipitation?
Weather
15
Name
Date
Key Concept Builder
Class
LESSON 1
Describing Weather
Key Concept What is weather?
Directions: Put a check mark in the correct column to answer the question about weather. Then explain each answer.
Does this fit the definition of weather?
Yes
No
Why or why not?
1. It has been raining where you live for
the past hour.
2. The average temperature in the summer
is 42°C.
3. The temperature decreases 5°C in one
hour and then decreases another 3°C in
the next hour.
4. The day began sunny, but now there are
plenty of clouds.
5. The region gets an average of 2.5 cm
of rain each year.
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6. You want to go on a bike ride, but you
decide to go outside to check for dark
clouds.
7. Heavy rainstorms are predicted for the
next two hours, after which the sky
should clear.
8. Ice formations are present across the
region throughout the year.
9. Plants that require high amounts of
moisture year-round grow in the area.
10. The clouds seem to be moving quickly,
and the wind has started to blow
harder.
11. The day began sunny, but now you wish
you had an umbrella.
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Weather
Name
Date
Key Concept Builder
Class
LESSON 1
Describing Weather
Key Concept What variables are used to describe weather?
Directions: Use the clues and the terms listed below to complete the puzzle.
air pressure
air temperature
barometric pressure
humidity
precipitation
relative humidity
dew point
1
2
3
4
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5
6
7
Clues
Across
2. another term for air pressure
4. when water, in liquid or solid form,
falls from the atmosphere
5. measure of the average kinetic energy
Down
1. temperature at which air becomes fully
saturated
3. pressure that a column of air exerts on
the air or surface below it
of molecules in the air
6. amount of water vapor in the air
7. amount of water vapor in the air
relative to the maximum amount of
water vapor the air can contain at that
temperature
Weather
17
Name
Date
Class
Key Concept Builder
LESSON 1
Describing Weather
Key Concept What variables are used to describe weather?
Directions: Answer each question or respond to each statement in the space provided.
Variable
Definition
How is the variable measured?
1.
2.
Air pressure
3.
4.
Wind
5.
6.
Humidity
7.
8.
Relative humidity
9.
10.
Dew point
11.
12.
Clouds and fog
13.
14.
Precipitation
15.
16.
18
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Air temperature
Weather
Name
Date
Key Concept Builder
Class
LESSON 1
Describing Weather
Key Concept How is weather related to the water cycle?
Directions: On the line before each statement, write T if the statement is true and F if the statement is false.
1. Precipitation, condensation, and evaporation are important to the water cycle.
2. The water cycle is a natural process.
3. In the water cycle, water is constantly added to the atmosphere, where it builds
up over time.
4. Most water enters the atmosphere through surface runoff.
5. Water vapor warms as it rises in the atmosphere.
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6. Water vapor that evaporates eventually condenses.
7. Clouds form from liquid water and ice.
8. Evaporation occurs when water falls from clouds.
9. Water enters the atmosphere when it condenses.
10. Thermal energy causes water at the ocean’s surface to evaporate.
Weather
19
Name
Date
Enrichment
Class
LESSON 1
The Power Plant for Weather
The Sun’s energy powers the weather,
from cloud formation to the entire water
cycle. In fact, there would be no weather at
all if we didn’t have the Sun. Earth receives
less than a billionth of the energy that the
Sun produces, but that is enough to run
the water cycle, drive the weather, move
ocean currents, maintain wind patterns,
and enable photosynthesis.
Electromagnetic Energy
What causes weather?
The Sun’s energy reaches Earth’s surface
as parallel rays. If Earth were a flat disk that
faced the Sun, all parts of the surface would
receive an equal amount of energy. But
Earth presents a curved surface to the
incoming electromagnetic radiation from
Applying Critical-Thinking Skills
Directions: Respond to each statement.
1. Predict what Earth might be like without the Sun.
2. Explain in terms of angle of incidence why equatorial rain forests experience more
vegetative growth and a wetter climate than other parts of Earth.
3. Summarize how typical weather conditions in the Amazon might differ from typical
weather experienced in Anchorage, Alaska.
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Weather
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The Sun drives most surface processes on
Earth. The energy to do this work arrives on
Earth’s surface in the form of electromagnetic
energy. Electromagnetic energy is radiated
by the Sun in waves. The range of
electromagnetic energy Earth receives is the
electromagnetic spectrum. This spectrum
includes rapid, high-energy gamma rays;
X-rays; ultraviolet rays; visible light; infrared;
microwaves; and long, slow radio waves.
Each of these types of waves is distinguished
by wavelengths in a particular range.
the Sun. Only one place on Earth—the
equator—receives rays from the Sun
straight on. All other areas receive rays at
the angle of incidence. A location near the
equator receives rays at a high, or more
intense, angle of incidence, and a location
near a pole receives rays at a low, or less
intense, angle of incidence. The angle of
incidence becomes increasingly lower with
increasing latitude north or south. As Earth
proceeds in its yearly orbit around the Sun,
the angle of incidence varies with the
seasons, except at the equator.
Variations in the intensity of energy
from the Sun received on Earth’s surface
cause thermal energy to be unequally
distributed in the atmosphere. This energy
tends to move toward a more even
distribution. The movement of energy
results in more or less constant changes in
the atmosphere, which cause the weather.
Weather can be defined as the changes
in the atmosphere at a given location for a
short period of time. Earth’s rotation and
orbit affect how much energy the parts of
the surface receive from the Sun at any
given time. Heating and cooling on a daily
basis and on an annual basis drives changes
in temperature, air pressure, winds,
precipitation, humidity, cloud cover, and
storms—all of which are weather variables.
Name
Date
Class
Challenge
LESSON 1
Tracking Temperature
Select a position outside your home where you can comfortably and easily check and
record the outside temperature at least twice each day for a week. This will be your
checkpoint. A convenient way to check the temperature is with a thermometer that hangs
outside a window and can be read from the inside.
Collect and Compare Data
Choose two times during the day when you can record a low temperature and a high
temperature. For example, record the temperature when you first get up in the morning,
and again when you first come in from school in the afternoon. A sample chart is shown
below. Choose a scale for your graph that is appropriate for the time of year.
When you have a week’s high and low temperatures in your chart, create a graph to display
your data. Plot the lows in one color, and plot the highs in another color.
Temperature Data for Checkpoint:
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
High
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Low
Directions: Respond to each statement on the lines provided.
1. Identify the high and low temperatures for the week using the graph and your data.
2. Calculate the average high and average low temperatures for the week. Explain your
method.
3. Explain how a meteorologist can use data like these to predict temperature changes
from day to day and from year to year.
Weather
21
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