Planet Earth:
Seasons and Weather
Contents
1. Night and Day (Pasco)
2. Seasons
GLE’s 3rd: 1-6, 8-12, 54, 55
4th: 1-7, 9-13, 66
GLE’s 3rd: 1,5,6,7,9,10,19,55
4th: 1,7,8,10,11,23,57,6
3. Season (Pasco)
GLE’s 3rd : 1-6, 8-12,54, 55
4th: 1-7, 9-13, 68
4. Water Cycle
GLE’s 3rd:1,5,6,9.10,48,22,
4th: 1,6,7,10,12,58
5. Evaporation and Condensation
In the Water Cycle (Pasco)
GLE’s 3rd: 1-12, 48
4th: 1-13, 58
6. Waters Role in Climate (Pasco)
7. Weather Tracking
8. Natural Disasters
GLE’s 3rd: 1-12, 48, 54, 55
4th:: 1-13, 57, 58
GLE’s 3rd: 1,5,6,7,9,10,15,19,49
4th: 1, 6,7,10,12,59,60,61
GLE’s 3rd: 1,9,15,17,47
4th: 1,10,22,60,63
Internet Resources
Great site for animations/pictures
http://www.classzone.com/books/earth_science/terc/navigation/visualization.cfm
Seasons
http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html
http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html
Day and Night
http://www.onr.navy.mil/focus/spacesciences/observingsky/motion1.htm
http://www.timeanddate.com/worldclock/sunearth.html
Water Cycle
http://earthguide.ucsd.edu/earthguide/diagrams/watercycle/
http://ga.water.usgs.gov/edu/watercyclesummary.html
Weather
http://www.nationalgeographic.com/forcesofnature/resources/
http://www.usatoday.com/weather/default.htm
http://www.nws.noaa.gov/
http://www.weather.com
http://www.education.noaa.gov/tweather.html#General
http://www.climate-zone.com/
Night and Day
(Pasco Lab Activity)
GLEs
3rd Grade: SI 1-6, 8-12; ESS 54, 55
4th Grade: SI 1-7, 9-13; ESS 66
Correspondence to Textbook Activities
3th Grade: Unit 6 p. 267; Unit 7 p. 291; p. 323
4th Grade: Unit 6 p. 335
Driving Question
What causes us to have night and day?
Words for Word Wall
Rotation
Orbit
Illuminate
Revolution
Materials and Equipment
For each student or group:
 GLX or Spark
 Index card (2), 3 in. x 5 in.
 Light sensor
 Marker (dark color)
 Utility lamp or flashlight
 Tape
Safety
Add this important safety precaution to your normal laboratory procedures:

Do not shine any light directly into others' eyes.
Thinking about the Question (Read aloud to students and discuss.)
People have observed the sky for many thousands of years. The most obvious objects in the sky, of
course, are the sun in the day and the moon at night. Ancient people thought that the sun and the
moon both revolved around the earth. We no longer believe this because we know that the earth
rotates, or spins like a basketball on the tip of a player's finger. It is this rotation that is the cause
for our night and day on Earth. Rotation is one of the types of motion found in our solar system and
in the universe. Can you think of any other types of motion that occur in the solar system?
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Ancient people were excellent observers of the night sky. They also had the benefit of very dark
nights, in which the stars, the planets, and even the Milky Way—our own galaxy—were visible. This
was because their only source of light was fire, so consequently there was very little light pollution.
In addition, many of the world's great cultures were extremely interested in astronomy for religious
or for practical reasons, such as knowing when to plant and harvest crops. To these observers, it was
evident that the celestial bodies traveled around the earth. How would their observations have been
different if this type of motion really was occurring? Discuss in your group how the path traveled by
the sun and moon would appear if the earth was not rotating, and the sun and the moon were
orbiting the earth. Be prepared to share your thoughts with the rest of the class.
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In this activity you will be working within your group to model Earth's rotational motion and how
the sun's light falls upon the rotating planet. You will observe how this rotation causes night and
day to happen in a regular, repeating cycle. You will need to have one volunteer to play the role of
the earth, and a second volunteer to play the role of the sun.
Investigating the Question
Part 1 – Making predictions
1. Write your predictions for the following:
a.
What will happen to the level of light that falls from a light source onto the light sensor as
it is rotated in a complete circle by one of your classmates?
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________________________________________________________________________________________
b.
If the light sensor is rotated several times, what will a graph of light intensity versus time
look like?
________________________________________________________________________________________
________________________________________________________________________________________
c.
Would you be able to tell from the graph how many rotations the light sensor made?
Explain your reasoning.
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d.
If the student playing the role of the earth has the direction "east" taped to his or her left
shoulder and the direction "west" taped to his or her right shoulder, which direction will
the student turn to make the "sun" appear to rise in the east and set in the west?
________________________________________________________________________________________
Part 2 – Measuring light through one rotation
In this activity one group member volunteers to play the role of the earth, and will be responsible for
data recording. Another group member volunteers to play the role of the sun, and will be responsible
for shining the lamp or flashlight on the "earth." Data recording is carried out with the room
darkened.
2. Mark one index card with a large "E" and the other with a large "W."
3. Tape the compass direction east to the "earth's" left shoulder, and tape west to the "earth's" right
shoulder.
4. Start a new experiment on the data collection system.
5. Connect a light sensor to the data collection system. Select the medium sensitivity range
(0–260 lux) for the light sensor.
6. Display Light intensity on the y-axis of a graph with Time on the x-axis.
7. The "earth" begins by holding
the light sensor pointing
outward, and facing away
from the "sun," whose light
should be shining on the
"earth's" back.
8. Begin data recording.
9. The "earth" turns slowly and
steadily in a circle so that
the left, or "eastern,"
shoulder is illuminated
first, and so that the
complete rotation takes
between 30 and 40
seconds. You may have to
practice a few times at
first.
10. After completing the one rotation, stop data recording.
11. Observe your graph of light intensity data. You may need to adjust the scale of the graph to view
all of your data. Record your observations below.
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________________________________________________________________________________________
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Part 3 – Measuring light through a series of rotations
As in Part 2, in this activity one group member volunteers to play the role of the earth, and will be
responsible for data recording. Another group member volunteers to play the role of the sun, and will
be responsible for shining the lamp or flashlight on the "earth." Data recording is carried out with
the room darkened.
12. The "earth" begins by holding the light sensor pointing outward, and facing away from the "sun,"
whose light should be shining on the "earth's" back.
13. Begin data recording.
14. The "earth" turns slowly and steadily in circles so that the left, or "eastern," shoulder is
illuminated first, and so that each rotation takes between 20 and 30 seconds. The "earth"
should rotate through at least 5 complete days and nights.
15. After completing the rotations, stop data recording.
16. Observe your graph of light intensity data. You may need to adjust the scale of the graph to view
all of your data. Record your observations below.
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________________________________________________________________________________________
Answering the Question
Analysis
1. How did your predictions from Part 1 compare to your results in Part 2?
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2. How did your predictions from Part 1 compare to your results in Part 3? How many cycles of
night and day did your group make? How can you tell?
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3. The term "solar noon" refers to the point when the sun has risen to its maximum height in the
sky before appearing to begin its decline toward the west. Examine your light intensity versus
time data. Can you tell from your data when it was "solar noon" at the light sensor on the
"Earth's" surface? Explain your thinking.
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4.
Imagine you were living 2500 years ago in ancient Greece, and did not have access to a light
sensor to assist in your observations of the night or day sky. How might you have used shadows
cast by trees or other objects to determine when it was noon? Explain your reasoning.
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5. Examine your data from Part 3 again. Can you tell how much time passes between the brightest
point, or solar noon, of one day and the darkest point of the "night" by looking at the graph? You
may need to adjust the scale of the axes or zoom in to a portion of the graph. Selecting specific
data points in your graph may help you in your analysis.
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Multiple Choice

Circle the best answer or completion to each of the questions or incomplete statements below.
1. If it is midnight at your location on Earth's surface, what is true of your position on Earth?
A. You are located on the side of our planet that is directly opposite the sun.
B. The sun has traveled around behind your position on Earth's surface.
C. You are located on Earth's surface at a right angle to the sun.
2. Which term is used to describe the motion that is responsible for Earth's nights and days?
A. Spinning
B. Axis-tilt
C. Rotation
3. Which statement best describes solar noon?
A. The time at which a location on the earth's surface is facing directly toward the sun.
B. The exact moment in time when the earth has completed one rotation.
C. The point in the earth's rotation when a location on the earth's surface is facing away
from the sun.
4. Suppose there is a planet that takes 52 hours to rotate. How long is one complete night and day
cycle on that planet?
A. 24 hours
B. 360 hours
C. 52 hours
5. The sun and moon appear to us to rise in the east and set in the west because the earth
A. Rotates at a steady rate, turning through 360 degrees in the same amount of time for each
rotation.
B. Rotates on its axis, which is an imaginary line that goes through the earth's center from
the North to the South Poles.
C. Rotates in a counterclockwise direction when viewed from the North Pole.
6. If our planet did not rotate on its axis every 24 hours, which of the following would be true?
A. The sun would appear to move through the sky
B. The moon would appear to rise in the west and set in the east
C. There would be no cycle of night and day
True or False

Enter a "T" if the statement is true or an "F" if it is false.
_____________ 1. Because the sun and the moon appear to travel across the sky from east to west,
ancient people thought the earth did not rotate, but that these bodies travel in a
circular path around our planet.
_____________ 2. From our view on the earth's surface, it is not possible to determine which is
moving – the earth or the sun.
_____________ 3. Rotation and revolution refer to the same types of motion.
_____________ 4. If you watch a sunset, you are seeing the moment in time where the earth's
rotation carries you from the lighted part of the planet to the part that is not
illuminated.
_____________ 5. The only place on Earth to see the sun appear to rise in the west and set in the
east is on the equator.
Night and Day
(Student Sheet)
In this activity you will be working within your group to model Earth's rotational
motion and how the sun's light falls upon the rotating planet. You will observe how
this rotation causes night and day to happen in a regular, repeating cycle. At the
end of the activity you will be able to answer the questions: What causes us to
have night and day?
Prediction: (Answer on your lab sheet)
What will happen to the level of light that falls from a light source onto the light
sensor as it is rotated in a complete circle by one of your classmates?
Directions:
1. Jobs: a. One group member volunteers to play the role of the earth and will
be responsible for holding the light sensor.
b. Another group member volunteers to play the role of the sun, and
will be responsible for shining the flashlight on the "earth."
2. Tape the index card labeled east to the "earth's" left shoulder, and tape west
to the "earth's" right shoulder
3. Connect a light sensor to the data collection system and turn on system.
4. On the sensor; select the medium sensitivity range (0–260 lux) for the light
sensor (middle button).
5. Set up system to collect data. Use
the quick guide to help.
6. The "earth" begins by holding the
light sensor pointing outward, and
facing away from the "sun."
7. The sun will point the light on
“earth’s” back.
8. Begin data recording.
9. The "earth" turns slowly
in a circle so that the left shoulder (marked East) is lit up by the sun first.
10. One complete turn should take you 30 seconds.
11. After completing the one rotation, stop data recording.
12. Observe your graph of light intensity data. You may need to adjust the scale
of the graph to view all of your data. Sketch the graph that you see on the
screen on your lab sheet.
13. Answer questions on your lab sheet.
Night and Day
(Student Sheet)
Prediction:
What will happen to the level of light that falls from a light source onto the light
sensor as it is rotated in a complete circle by one of your classmates?
Results:
(Lux)
Light Intensity
Changes of Light Intensity on a rotating object
5
10
15
20
25
30
35
40
Time (s)
Questions:
1. What happen to the level of light as “Earth” rotated?
2. Which direction (East or West) did the light source hit first?
3. When your front side was facing the light source, did your back side receive
any light? Explain your answer.
4. The light source is represented the sun. The person with the light sensor is
the earth. Answer the question based on what you observed with this
activity. When will earth have day time? When will earth have night time?
5. Which direction will the sun rise (day time starts) out of the sky? Which
direction will the sun set (night time starts)?
6. North America (where we live) is represented by your front side and the
Middle East(opposite side of earth) is represented by your back side. When
North America is having day time will the Middle East have day time or
night time? Explain your answer.
7. The term "solar noon" refers to the point when the sun has risen to its
maximum height in the sky before appearing to begin its decline toward
the west. Examine your light intensity versus time data. Can you tell from
your data when it was "solar noon" at the light sensor on the "Earth's"
surface? Explain your thinking.
8. If the light sensor (earth) is rotated several times, what will a graph of
light intensity versus time look like?
(Lux)
Light Intensity
Changes of Light Intensity on a rotating object
5
10
15
20
25
30
35
40
45
50
55
60
Time (s)
Use the light sensor to determine if you predicted the light intensity pattern
correctly.
9. Label the graph above where you think daytime occurs and nighttime occurs.
10. Look at the graphs that you have recorded. Can you tell how much time passes
between the brightest point, or solar noon, of one day and the darkest point of
the "night" by looking at the graph? Explain your answer.
Seasons
Objective:
Students will gain an understanding of how the tilt of the earth on its axis is the
cause for seasons on earth.
Background:
The seasons are the result of the tilt of the
Earth's axis. The Earth's axis is tilted from
perpendicular to the plane of the ecliptic by
23.45°. This tilting is what gives us the four
seasons of the year - spring, summer, autumn
(fall) and winter. Since the axis is tilted,
different parts of the globe are oriented
towards the Sun at different times of the year.
Summer is warmer than winter (in each hemisphere) because
the Sun's rays hit the Earth at a more direct angle during
summer than during winter and also because the days are much
longer than the nights during the summer. During the winter,
the Sun's rays hit the Earth at an extreme angle, and the days
are very short. These effects are due to the tilt of the Earth's axis.
Solstices
The solstices are days when the Sun reaches its farthest northern and southern
declinations. The winter solstice occurs on December 21 or 22 and marks the beginning of
winter (this is the shortest day of the year). The summer solstice occurs on June 21 and
marks the beginning of summer (this is the longest day of the year).
Equinoxes
Equinoxes are days in which day and night are of equal duration. The two yearly equinoxes
occur when the Sun crosses the celestial equator.
The vernal equinox occurs in late March (this is the beginning of spring in the Northern
Hemisphere and the beginning of fall in the Southern Hemisphere); the autumnal equinox
occurs in late September (this is the beginning of fall in the Northern Hemisphere and the
beginning of spring in the Southern Hemisphere).
Reasons for the Seasons
Important Facts
 The Earth revolves around the Sun.
 The North pole always points the same way as the Earth revolves around the Sun.
 The tilt of the Earth remains constant.
During a Year
The Earth takes 365.24 days to orbit the sun. As we move around the Sun during the year,
the amount of light each area of the planet receives varies in length.
When the Earth's axis points towards the Sun, it is summer for that hemisphere. Winter
can be expected when the Earth's axis points away. Since the tilt of the axis is 23 1/2
degrees, the north pole never points directly at the Sun.
The three reasons why we have Seasons
1. Tilt of the Earth
2. Revolution - The Earth revolves around the Sun.
Materials:
Flashlight
Markers
Dark room
Handouts
Globe (optional)
Internet
Getting Ready:
Attach the sheet of graph paper to a cardboard or copy graph paper on cardstock
to make the paper ridged.
Overview:
For the first part, students will hold a flashlight up to graphing paper to
determine the difference in the area of the light that hits the vertical and tilted
paper. The graph paper represents the earth and the flashlight represents the
sun. This activity can be used to with the Pasco lab activity or left out completely.
During discussion of part I show animation from website
http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html . This website
shows the sunbeam spread on the Earth during the year.
For the second part, with guidance the students will analysis an animation from the
above website. The animation shows the earth’s orbit around the sun. At the end
of both activities students will summarize the reason why Earth has seasons.
Literacy Connections:
o Sunshine Makes the Seasons by Franklyn M. Branley.
o The Reasons for Seasons by Gail Gibbons
Song
The Tilt of the Earth (sung to the tune of Mary Had a Little Lamb)
Earth's tilt makes the seasons change,
Season's change, seasons change,
Earth's tilt makes the seasons change,
They change all through the year.
Near the sun it's summertime,
Summertime, summertime,
Near the sun it's summertime,
The days are hot and bright
Far away it is wintertime,
Wintertime, wintertime,
Far away its wintertime,
The days are cold and gray.
Spring and fall are in=between,
In-between, in-between,
Spring and fall are in-between,
The days are cool or warm.
Earth's tilt makes the seasons change,
Season's change, seasons change,
Earth's tilt makes the seasons change,
They change all through the year.
Reasons for the Seasons (Part I)
(student sheet)
Purpose: To determine what happens to the amount of light reaching the paper as
the paper tilts.
Procedure:
1.
Hold the graph paper straight up and down, (perpendicular to the
ground).
2. Shine the flashlight directly at the graph paper.
3.
Be sure the flashlight is parallel to the floor and perpendicular to the paper
4. Trace the outline of the brightest part of the flashlight's beam on the graph
paper. (Label # 1)
5. Keeping the same distance from the paper to the flashlight, tilt the top part of
the graph paper backwards.
6. Trace the outline of the brightest part of the flashlight’s beam on the graph
paper. (Label # 2)
7. Count the number of squares in the area Label # 1 _________
Count the number of squares in the area Label # 2 _________
Questions:
1. Does the light spot on the graph paper always remain the same size (straight
paper to tilted paper). Explain your answer.
(more squares in the area the bigger the size)
2. Does the brightness of the light spot remain the same (straight paper to tilted
paper). Explain your answer.
3. Did the brightness from the flashlight change?
4. If the flashlight was a heated lamp, which path of light would bring more heat:
straight path or the angled path? Explain your answer.
Reasons for the Seasons (Part II)
(Teacher Instructions)
1. Connect to the websitehttp://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html
2. Set animation: a. Move figure person closer to the north pole.
b. Make sure the animation has labels.
c. Set to sunlight angle; view from side
3. Show the animations once all the way through with no explanations. Then a
second time moving the red marker on select winter/summer months.
a. Show the Earth orbit around the sun first.
Question: Did the Earth revolve or rotate around the sun? {revolve}
Question: Did the Earth become closer to the sun any time during its
revolution? {No}
Guided questions while moving the red marker:
Question: Look at the red line, this marks the northern hemisphere of the
Earth where we live: How does it tilt during the winter monthstoward the sun or away from the sun? {away from the sun}
Question: Looking at the same red line: How does the line tilt during the
summer months- toward the sun or away from the sun? {toward the sun}
b. Show the Earth with the sun rays animation.
Question: During the year, how did the sun rays change?
{changed angles that they hit the Earth}
Guide the students though the following questions by moving the red marker
through the different months.
Question: During the winter months are the sun rays at an angle or directly
over the figure? {hit the figure at an angle}
Question: What type of weather do we have during these winter months?
{cold}
Question: During the summer months are the sun rays at an angle or
directly over the figure? {hit the figure almost directly}
Question: What type of weather do we have during these summer months?
{hot}
Question: What is the relationship between angle of sun rays and the
weather that we feel? {colder when the rays are at an angle and warmer
when the sun rays are almost directly above}
4. Let the students in their groups answer the conclusion section of these
activities.
Reasons for the Season (Part II)
(student sheet)
Purpose: To use an animation of the earth’s orbit around the sun to determine why
we have seasons.
Questions
1. Does the Earth revolve or rotate around the sun?
2. Does the Earth become closer to the sun anytime while it moves around the
sun?
Look at the red line, this marks the northern hemisphere of the Earth where we
live.
3. How does it tilt during the winter months- toward the sun or away from the
sun?
4. How does the line tilt during the summer months- toward the sun or away from
the sun?
5. During the year, how do the sun rays change as they meet the Earth?
6. During the winter months, do the sun rays meet the northern hemisphere at an
angle or almost directly overhead?
7. What type of weather do we have during these winter months?
8. During the summer months, do the sun rays meet the northern hemisphere at an
angle or almost directly overhead?
9. What type of weather do we have during these summer months?
10. What is the relationship between the angles at which sun rays shine on the
northern hemisphere and the weather that we feel?
Conclusions
(student sheet)
Use the following word bank to help fill in the blanks.
high
more
winter
away from
towards
low
summer
less
1. If the sun rays hit the northern hemisphere on Earth at an angle, the light
intensity will be _____________ and we will feel __________ heat.
2. When the sun rays hit the Earth at an angle, the northern hemisphere is tilted
________________ the sun.
3. When the northern hemisphere is tilted away from the sun it is the
___________ season.
4. If the sun rays hit the northern hemisphere on Earth almost directly, the light
intensity will be _________________ and we will feel ___________ heat.
5. When the sun rays hit the Earth almost directly, the northern hemisphere is
tilted ___________ the sun.
6. When the northern hemisphere is tilted toward the sun it is the _________
season.
Answer the following question:
7. If the northern hemisphere is having summer season; what season would the
southern hemisphere experience? Explain your answer.
Using the conclusion statements above to write a sentence or two to explain
why the earth has seasons?
Seasons
(Pasco Lab Activity)
GLEs
3rd Grade: SI 1-6, 8-12; ESS 54, 55
4th Grade: SI 1-7, 9-13; ESS 68
Correspondence to Textbook Activities
3rd Grade: Unit 8 p. 355; p. 359
4th Grade: Unit 6 p. 329; p. 339
Driving Question
What makes us experience spring, summer, fall and winter?
Words for Word Wall
solstice
equinox
hemispheres
Tropic of Cancer
Tropic of Capricorn
equator
axis
tilt
revolution
orbit
rotation
seasons
poles
Materials and Equipment
For each teacher:
 Protractor
 Thumbtack or pushpin
 Scissors
 Sheet of card stock, 12” x 18”
 String, to suspend paper model (~1 m)
 Sticky tape
 Marking pens, various colors
For each student or group:
 GLX or Spark
 Light sensor
 Flashlight
 Meter stick or straightedge
Safety
Add these important safety precautions to your normal laboratory procedures:

Do not shine any light directly into others' eyes

Use caution with sharp objects such as scissors and compass points
Thinking about the Question
(Read aloud to the class and discuss; you may want to enhance
discussion with maps and/or a globe, pictures or video clips from
past Olympic events and pictures with scenes from the different
seasons of the year)
You have experienced bright, sunny days in the winter as well as in the summer. You have probably
noticed, however, that a winter sun is not able to warm you as much as a summer sun. In fact, if you
live in a climate that has very cold winters, you may even have observed that the sun can shine on
snow and ice all day long without melting it. How is it possible for the sun to shine so brightly, yet
give so much less warmth than it does in the summer? The answer lies in the fact that the sun’s light
strikes the northern hemisphere of the Earth at more of an angle in the winter, while in the summer
the sun’s light strikes the northern hemisphere of the Earth more directly.
As you know, the Olympic Winter Games are held every four years, always at a cold, snowy location.
Since the Games began in 1924 with the participation of sixteen European and North American
countries, they have always been held during the northern hemisphere’s winter, usually in February.
Likewise, the Summer Games have been held in the northern hemisphere’s summer. With only two
exceptions, Melbourne, Australia in 1956, and Sydney, Australia in 2000, the Summer Games have
been held in the northern hemisphere. Currently, over 200 nations participate in the Olympic
Summer Games. In your lab group, discuss the following questions:
1.
When do countries in the southern hemisphere experience summer and winter?
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2. If the Summer Games are held in Australia in July, in what season will the athletes compete?
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3. When could an alpine nation in the southern hemisphere, such as Argentina or Chile, host the
Winter Games?
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________________________________________________________________________________________
4. How would northern hemisphere athletes be able to train for the Winter Games if they were held
in the southern hemisphere?
________________________________________________________________________________________
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During the year, there are four dates that are very special because they divide the year into the four
seasons: winter, spring, summer, and autumn. These dates have been known since ancient times,
and used to mark and regulate many of our most important human activities, such as planting and
harvesting crops, organizing religious festivals, locating compass directions for navigation and for
situating certain types of buildings. These dates are the solstices and equinoxes.
You may already know that a solstice occurs in June and again in December, and that the equinoxes
occur in March and again in June. Discuss with your lab group members what season begins on each
of these dates. Does the same hold true for both hemispheres? Be prepared to share your thoughts
with the rest of the class.
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________________________________________________________________________________________
________________________________________________________________________________________
Investigating the Question
Part 1 – Making predictions
1.  Write your prediction for the following:
How will the light intensity change when you shine a flashlight almost straight on to the
light sensor compared to shining it at an angle to the light sensor?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Part 2 – Making a model of the Earth (To be completed by the teacher prior to lab
activity)
In this part of the activity, you will use your geometry math skills to construct a circle, several
diameters and chords, and to measure angles.
2.  Using the string and push pin, construct a large circle on your card stock. As you work, be
sure to mark the center of the circle to use as a landmark for some folds you will make in the
following steps.
3.  Cut out the circle. The circle represents the earth.
4.  Fold the circle in half, making sure the fold goes right through the center of the circle. This
crease represents Earth’s equator. Why is it so important that this fold makes a crease right
through the center of the circle?
5.  Fold the circle into quarters, forming a second crease that represents Earth’s polar axis, the
imaginary line that connects the north and south poles. To make this fold, first fold the circle
in half at the equator, then in half again. When you open the circle up, you will have made a
crease perpendicular to the equator.
6.  Use a meter stick or straightedge and marking pens to draw in the equator and label it with
its name. Also mark East and West on the appropriate end of the equator.
7.  Draw in and label the polar axis in the same way you did for the equator. Also mark North
and South on the appropriate end of the polar axis.
8.  Use the protractor to mark an angle of 23.5 degrees off the North Pole.
9.  Construct a radius that forms the 23.5 degree angle with the polar axis.
10.  Use the protractor to make three more radii, each forming 23.5 degree angles with the polar
axis, to the right and to the left of the north and south poles. Your radii should form an “X”
as in the diagram. These radii form diameters, which now represent the degree of Earth’s tilt
off its polar axis.
23.5°
11.  Construct a chord that connects the top of the “X.” This chord represents the Arctic Circle,
which is located at 66.5 degrees north latitude. Draw and label the Arctic Circle.
12.  Construct a chord that connects the bottom of the “X.” This chord represents the Antarctic
Circle, which is located at 66.5 degrees south latitude. Draw and label the Antarctic Circle.
Arctic Circle
Antarctic Circle
13.  Use the protractor to mark angles that are 23.5 degrees above and below each half of the
equator. Do not draw in these radii; make a mark on the circumference of the circle where
the radii would intersect.
14.  Construct a chord by connecting the two marks 23.5 degrees above the equator. This chord
represents the Tropic of Cancer, which is located at 23.5 degrees north latitude. Draw and
label the Tropic of Cancer.
15.  Construct a chord by connecting the two marks 23.5 degrees below the equator. This chord
represents the Tropic of Capricorn, which is located at 23.5 degrees south latitude. Draw and
label the Tropic of Capricorn.
Tropic of Cancer
Tropic of Capricorn
16.  Tape string carefully along the diameter that connects the left side of the Arctic Circle to the
right side of the Antarctic Circle. If you let your earth model hang from the string, the North
Pole should be angled to the right (at about where 1:00 would be on the face of a clock).
Attach the string so that it extends beyond the edges of the circle.
String
Tape
Part 3 – Modeling and measuring Earth’s seasons (To Be Completed by students)
17.  Use tape to attach the light sensor to your earth model, directly on the Tropic of Cancer so
that the black opening is even with the circumference. By measuring light intensity on the
Tropic of Cancer, which hemisphere are you testing for your seasons?
18.  Connect the light sensor to the data collection system. Select the maximum sensitivity range
(0 – 2.6 lux) for the light sensor.
19.  Display Light Intensity on the y-axis of a graph with Time on the x-axis.
20.  Hold the earth model by the string, both from the top and the bottom. If necessary, tape your
paper earth to the wall or blackboard according to your teacher’s instructions. Notice how the
axis tilt causes the Tropics of Cancer and Capricorn to be angled.
21.  Model the sun as follows: standing about a meter away from the model, shine a flashlight
onto the opening of the light sensor. Be sure to hold the flashlight so its beam is horizontal
(parallel to the floor).
22.  Darken the room.
23.  Begin data recording.
24.  After you have recorded between 20 and 40 seconds of light intensity data, stop recording.
25.  Remove the tape from the light sensor. Now tape the light sensor on the Tropic of Cancer
pointing in the opposite direction.
26.  Move the model earth around to the opposite side of the sun.
27.  Shine the flashlight onto the opening of the light sensor, as you did before. Hold the
flashlight so its beam is horizontal (parallel to the floor), at the same height above the
ground as before. Why is it so important to the model that the sun remains in the same place
all the time?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
28.  Begin data recording.
29.  After you have recorded between 20 and 40 seconds of light intensity data, stop recording.
30.  Observe your graph of light intensity data. You may need to adjust the scale of the graph to
view all of your data. Record your observations below.
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
31.  Save your experiment according to your teacher's directions.
Answering the Question
Analysis
1. How did your predictions from Part 1 compare to your results in Part 3?
________________________________________________________________________________________
________________________________________________________________________________________
2. What season were you modeling when the north pole of your paper earth was tilted toward the
flashlight? What season was modeled when the North Pole was tilted away from the sun?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
3.
Review your graph of light intensity versus time. What evidence do you see in your data that
different amounts of light energy strike the earth’s surface during different seasons?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
4.
Recall the demonstration at the beginning of this lab activity involving the flashlight shining on
the graph paper. How does this demonstration relate to the angle of the light hitting the light
sensor on your paper Earth?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
5. According to the work you did with your model Earth, is it possible for the part of the model
above the Arctic Circle to receive no light from the flashlight’s beam? If so, when is this possible
(which season were you modeling at the time)?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
6. Based on your knowledge of geography and of Earth’s night and day cycle, where and when does
this actually happen?
________________________________________________________________________________________
________________________________________________________________________________________
7. What would happen if the Earth was not tilted on its axis?
_________________________________________________________________________________________
____ ____________________________________________________________________________________
8. The Tropic of Cancer in the northern hemisphere marks the farthest point north on the earth
where the sun’s rays strike the earth’s surface directly straight on. This happens just once in
each year. On which of the four special days (equinoxes or solstices) and at what time in the day
does this happen?
________________________________________________________________________________________
________________________________________________________________________________________
9. Based on earlier class discussion and on your light intensity data, why do you think that the
surface of the earth in the Northern Hemisphere receives more of the sun's light and heat energy
in the summer compared to the winter?
________________________________________________________________________________________
________________________________________________________________________________________
Multiple Choice

Circle the best answer or completion to each of the questions or incomplete statements below. You
may want to look at a globe as you answer these questions.
1. Farmers in ancient Egypt would have awaited which of these special days to signal the wait
for the Nile River’s flood and the beginning of the spring planting season?
a. March equinox
b. June solstice
c.
September equinox
2. Inhabitants of the
experience winter between June and September.
a. Equatorial region
b. Southern hemisphere
c.
Northern hemisphere
3. The Olympic Winter Games are held every four years during
the perspective of the inhabitants of the southern hemisphere.
a. The winter
b. The spring
c.
The summer
, from
4. Which of the following does not actually happen?
a. Earth travels in an elliptical path around the sun every 365 days, causing a regular
cycle of summer, autumn, winter, and spring we call the seasons.
b. The axis on which the earth is tilted shifts back and forth to vary the North Pole’s
angle, creating the seasons.
c.
In part of the earth’s trip around the sun, the north pole happens to be tilted toward
the sun, while in the opposite part of the trip, it happens to be tilted away from the
sun.
5. The Tropic of Capricorn is the point farthest south on the earth’s surface where:
a. The solstices can occur
b. Ancient people would have been able to observe an equinox
c.
Light from the sun strikes the earth’s surface directly
6. Light from the sun that strikes the earth’s surface is less intense when it:
a. Does not spread out at all
b. Strikes the surface directly
c.
Spreads out over a larger area
7. Organize the following in order from the least amount of the sun’s energy to the greatest
amount of the sun’s energy falling on one location:
a. June solstice in New Zealand, September equinox in New Zealand, December solstice
in New Zealand
b. June solstice in Canada, September equinox in Canada, December solstice in Canada
c.
December solstice in New Zealand, September equinox in New Zealand, June solstice
in New Zealand
8. Which best describes the arrival of spring in the northern hemisphere?
a. As the earth experiences September equinox, its path around the sun brings it closer
to having the North Pole tilted directly away from the sun.
b. As the earth experiences March equinox, its path around the sun brings it closer to
having the North Pole tilted directly toward the sun.
c.
As the earth experiences December solstice, its path around the sun brings it to the
point where the North Pole is tilted directly away from the sun.
9. Which statement is not accurate?
a. Rotation refers to the earth spinning on its axis, giving us the regular cycle of night
and day.
b. Revolution refers to the earth traveling in an elliptical path or orbit around the sun,
giving us the regular cycle of seasons.
c.
The terms rotation and revolution refer to the same types of motion found throughout
the solar system.
Key Term Challenge

Fill in the blanks from the randomly ordered words below. Note that not all of the words may be
used:
solstice
equinox
hemispheres
Tropic of Cancer
Tropic of Capricorn
equator
axis
tilt
revolution
orbit
rotation
seasons
poles
1. A/an
occurs once in June, when the day is longest in the northern
hemisphere, and once in December when the day is shortest in the northern hemisphere.
2. The
is located at zero degrees latitude, meaning that it is neither north
nor south, but exactly in the middle, while the
are located at 90 degrees
of latitude.
3. On Earth, it takes 365 days to complete one
and to experience all of the
seasons, while it takes 24 hours to complete one
and experience a
complete cycle of night and day.
4. The
are the result of the earth’s tilt on its axis relative to its path
around the sun.
5. The earth is divided into two
which experience opposite seasons
during any given month.
6. At 23.5 degrees of south latitude there is an imaginary line, called the
.
on maps, and marking the farthest point south that the sun’s rays strike the
earth directly.
7. Earth’s
is tilted by 23.5 degrees, with the result that we experience
seasons because the surface of our planet receives sunlight at different angles depending on our
path around the sun.
Making a model of the Earth
In this part of the activity, you will use your geometry math skills to
construct a circle, several diameters and chords, and to measure angles.
1. Using the string and push pin construct a large circle on your card stock. As you
work, be sure to mark the center of the circle to use as a landmark for some
folds you will make in the following steps.
2. Cut out the circle. The circle represents the earth.
3. Fold the circle in half, making sure the fold goes right through the center of
the circle. This crease represents Earth’s equator.
4. Fold the circle into quarters, forming a second crease that represents Earth’s
polar axis, the imaginary line that connects the north and south poles. To make
this fold, first fold the circle in half at the equator, then in half again. When you
open the circle up, you will have made a crease perpendicular to the equator.
5. Use a meter stick or straightedge and marking pens to draw in the equator and
label it with its name. Also mark East and West on the appropriate end of the
equator.
6. Draw in and label the polar axis in the same way you did for the equator. Also
mark North and South on the appropriate end of the polar axis.
7. Use the protractor to mark an angle of 23.5 degrees from the polar axis in the
Northeast direction.
8. Construct a radius with a dotted line that forms the 23.5 degree angle with the
polar axis.
9. Use the protractor to make one more radius, forming 23.5 degree angle with
the polar axis in the Southwest direction. These radii form a diameter, which
now represents the degree of Earth’s tilt off its polar axis.
10. Measure 23.5 degree angle from the polar axis in the Northwest direction.
Place a mark at the edge of the circle.
11. Measure 23.5 degree angle from the polar axis in the Southeast direction.
Place a mark at the edge of the circle.
12. Construct a chord at the North Pole between the 23.5 degree marks. This
chord represents the Arctic Circle, which is located at 66.5 degrees north
latitude. Draw and label the Arctic Circle.
13. Construct a chord at the South Pole between the 23.5 degree marks. This
chord represents the Antarctic Circle, which is located at 66.5 degrees south
latitude. Draw and label the Antarctic Circle.
Arctic Circle
Antarctic Circle
14. Use the protractor to mark angles that are 23.5 degrees above and below each
half of the equator. Do not draw in these radii; make a mark on the edge of the
circle.
15. Construct a chord by connecting the two marks 23.5 degrees above the equator.
This chord represents the Tropic of Cancer, which is located at 23.5 degrees
north latitude. Draw and label the Tropic of Cancer.
16. Construct a chord by connecting the two marks 23.5 degrees below the equator.
This chord represents the Tropic of Capricorn, which is located at 23.5 degrees
south latitude. Draw and label the Tropic of Capricorn.
17. Tape string carefully along the diameter that connects the left side of the
Arctic Circle to the right side of the Antarctic Circle. If you let your earth
model hang from the string, the North Pole should be angled to the right (at
about where 1:00 would be on the face of a clock). Attach the string so that it
extends beyond the edges of the circle.
String
Tape
Reasons for the Seasons (Part I)
(student sheet)
Purpose: To determine the light intensity change when the sun hits the earth
at different angles.
Directions:
1. Write your prediction on your answer sheet.
2. Use tape to attach the light sensor to your earth model, directly on the Tropic
of Cancer so that the black tip is at the edge of the circle. By measuring
light intensity on the Tropic of Cancer you are measuring the light intensity
on the northern hemisphere.
3. Connect the light sensor to the data collection system. Select the maximum
sensitivity range for the light sensor.
4. Display Light Intensity on the y-axis of a graph with Time on the x-axis. See
the quick guide for instructions.
5. Hold the earth model by the string, both from the top and the bottom. If
necessary, tape the string to the wall according to your teacher’s
instructions. Notice how the axis tilt causes the Tropics of Cancer and
Tropics Capricorn to be angled. The earth has a normal tilt of 23.5 degrees.
6. Model the sun as follows: standing about a meter away from the model, shine a
flashlight toward the light sensor. The flashlight should be even with the
equator of your earth model. Be sure to hold the flashlight so its beam is
horizontal (parallel to the floor).
7. Darken the room.
8. Begin data recording.
9. After you have recorded 20 seconds of light intensity data, stop recording.
10. Remove the tape from the light sensor. Now tape the light sensor on the Tropic
of Cancer pointing in the opposite direction.
11. Move the model earth around to the opposite side of the sun.
12. Shine the flashlight onto the opening of the light sensor, as you did before.
Hold the flashlight so its beam is horizontal (parallel to the floor), at the
same height above the ground as before.
13. Begin data recording.
14. After you have recorded of 20 seconds light intensity data, stop recording.
15. Observe your graph of light intensity data. You may need to adjust the scale of
the graph to view all of your data. See quick guide for instructions.
16. Answer questions on your worksheet.
Reason for the Seasons (Part I)
(Student Sheet)
Prediction:
How will the light intensity change when you shine a flashlight almost straight
on to the light sensor compared to shining it at an angle to the light sensor?
Results:
How did the light intensity change when the flashlight beams hit the light sensor
at an angle (first recording) compared to the flashlight beams hit almost straight
on the light sensor (second recording)?
Questions:
The light sensor is attached to a model of the Earth and the flashlight represents
the sun.
1. The first recording represents the northern hemisphere of the Earth model
tilted away from the sun. How did the sun rays reach the northern hemisphereat an angle or almost straight on the Earth?
2. The second recording represents the northern hemisphere of the Earth model
tilted toward the sun. How did the sun rays reach the northern hemisphere- at
an angle or almost straight on the Earth?
3. More light intensity means more heat from the sun reaching the Earth. When
will the northern hemisphere feel more heat from the sun- when it is tilted
toward the sun or tilted away from the sun?
4. Less light intensity means less heat from the sun reaching the Earth. When will
the northern hemisphere feel less heat from the sun- when it is tilted toward
the sun or tilted away from the sun?
5. Think of the weather that we feel during the winter season. When would the
northern hemisphere have winter- when it is tilted toward the sun or tilted
away from the sun?
6. Think of the weather that we feel during the summer season. When would the
northern hemisphere have summer- when it is tilted toward the sun or tilted
away from the sun?
7. Based on your answers above, why do you think that the surface of the earth in
the northern hemisphere receives more of the sun's light and heat energy in
the summer compared to the winter?
8. Why was it important to keep the flashlight (the sun) in one place during the
activity?
9. What would happen if the Earth was not tilted on its axis? Explain your answer.
More on Seasons
Directions: Read the passages and answer the questions that follow.
During the year, there are four dates that are very special because they divide the year
into the four seasons: winter, spring, summer, and autumn (fall). These dates have been
known since ancient times, and used to mark and regulate many of our most important
human activities, such as planting and harvesting crops, organizing religious festivals,
locating compass directions for navigation and for situating certain types of buildings.
These dates are the solstices and equinoxes.
The solstice occurs in June and again in December, and that the equinoxes occur in March
and again in September. What season begins on each of these dates. Does the same hold
true for both hemispheres? Be prepared to share your thoughts with the rest of the class.
___________________________________________________________
___________________________________________________________
___________________________________________________________
As you know, the Olympic Winter Games are held every four years, always at a cold, snowy
location. Since the Games began in 1924 with the participation of sixteen European and
North American countries, they have always been held during the northern hemisphere’s
winter, usually in February. Likewise, the Summer Games have been held in the northern
hemisphere’s summer. With only two exceptions, Melbourne, Australia in 1956, and Sydney,
Australia in 2000, the Summer Games have been held in the northern hemisphere.
Currently, over 200 nations participate in the Olympic Summer Games. In your lab group,
discuss the following questions:
1. When do countries in the southern hemisphere experience summer and winter?
2. If the Summer Games are held in Australia in July, in what season will the athletes
compete?
3. When could an alpine nation in the southern hemisphere, such as Argentina or Chile,
host the Winter Games?
Water Cycle
Objective:
Students will be able to observe the water cycle and understand how water moves
through living and nonliving objects on earth.
Materials:
Handouts
9 dice (one dice per station)
Background:
The Water Cycle (also known as the hydrologic
cycle) is the journey water takes as it
circulates from the land to the sky and back
again.
The Sun's heat provides energy to evaporate
water from the Earth's surface (oceans, lakes,
etc.). Plants also lose water to the air (this is
called transpiration). The water vapor
eventually condenses, forming tiny droplets in clouds. When the clouds meet cool air over
land, precipitation (rain, sleet, or snow) is triggered, and water returns to the land (or
sea). Some of the precipitation soaks into the ground. Some of the underground water is
trapped between rock or clay layers; this is called groundwater. But most of the water
flows downhill as runoff (above ground or underground), eventually returning to the seas as
slightly salty water.
Living animals also move water about. Water, either directly consumed as liquid or
extracted from food, is carried within bodies. It then leaves as a gas during respiration,
is excreted through urine and feces or may evaporate from the skin as perspiration.
Getting Ready:
1. Place water reservoir signs around the classroom or hallway. Leave enough
space in between the stations for students to move around.
2. Divide the class into 9 groups.
Overview:
1. Distribute the scorecards and dice to each group.
2. Tell students that each group represents a water molecule that will be followed
for a brief period of time and that they should record where the molecule is,
what happens to it. and where it goes next during this game.
3. Show the stations to the students and randomly distribute the groups to their
initial stations.
4. Explain to them that they should record their current station on the scorecard
and should move to ten more stations. Their movement will be determined by
the number produced from rolling their die and the action corresponding to the
numbers posted at their station.
5. Once all groups have finished the game. Have the students make observations
about the movement of the water molecules. Guide them to an understanding
that water moves through air, water(oceans, rivers), animals, plants and ice.
Water mainly is found in the atmosphere and oceans. Also help them to realize
that there is no set pattern for the movement of water molecules.
6. Have the groups write a story or draw a picture of their water molecules
journey and share with the class.
Investigating Evaporation and Condensation in the Water Cycle
(Pasco Lab Activity)
GLEs
3rd Grade: SI 1-12; ESS 48
4th Grade: SI 1-13; ESS 58
Correspondence to Textbook Activities
3rd Grade: Unit 8 p. 341
Driving Question
Where on the earth is our water found?
Words for Word Wall
Water cycle
Relative humidity
Condensation
Evaporation
Precipitation
Materials and Equipment
For each student or group:
 GLX or Spark
 Water, cold
 Weather/Anemometer sensor
 Water, warm
 Beaker or a glass, 400 mL
 Cup, paper or plastic, filed with ice
 Hand lens or magnifying glass
 Tape
 Aluminum foil, 10 cm × 10 cm
 Paper towel
Safety
Add this important safety precaution to your normal laboratory procedures:

Warm water should not exceed 40 degrees Celsius. Severe burns may result.
Thinking about the Question (Discuss in groups, then as a class.)
Talk with your lab group members and generate a list of places where water is found (for example, in
a lake, stream, clouds, et cetera.) Write your list below.
________________________________________________________________________________________
________________________________________________________________________________________
In your list, what places have water in the form of a liquid, solid (ice or snow), or a vapor? Sort your
list above into the following categories.
Liquid:
________________________________________________________________________________________
Solid (ice):
________________________________________________________________________________________
Gas (vapor):
________________________________________________________________________________________
Water moves around the earth in what is known as the water cycle. You have listed where the water
is on earth. What do you know about how it moves around? Be prepared to share your understanding
with the class.
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
You have looked at where water can be found on the earth and how much is in various areas. How do
you think water moves from place to place? Where does water go? Get together with your group
members and describe this aspect of the water cycle. Include in your description your understanding
of how water naturally goes upward. Be prepared to discuss your thoughts with the class.
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Investigating the Question
Part 1 – Making predictions
1.  Write your predictions for the following:
a.
Will the relative humidity be higher above a dry surface or one from which water is
evaporating? Explain your reasoning.
________________________________________________________________________________________
________________________________________________________________________________________
b.
How will the relative humidity above cold water compare to the relative humidity above
warm water?
________________________________________________________________________________________
________________________________________________________________________________________
c.
Will the relative humidity above ice be higher or lower compared to the relative humidity
above cold or warm water?
________________________________________________________________________________________
________________________________________________________________________________________
Part 2 – Evaporation above cold water
2.  Obtain a piece of smooth aluminum foil and enough cold water to dampen a paper towel.
3.  Dampen the paper towel. Wipe the aluminum foil with the damp paper towel and observe it
for a few minutes. It may be helpful to view it with a magnifying glass.
4.  Try watching the smallest drop of water you can find on the foil. What happens to the water
on the surface of the aluminum foil? Where do you think the water is going? Be prepared to
discuss your thoughts with the class.
________________________________________________________________________________________
5.  Start a new experiment on the data collection system.
6.  Display Relative Humidity on the y-axis of a graph with Time on the x-axis.
7.  Place the relative humidity sensor face down on top of an empty 400-mL beaker. Use tape to
secure the relative humidity sensor on the rim of the beaker so the sensor openings that
contain the sensing elements are directly over the inside of the beaker. Make sure the sensor
is oriented "face down," so that the lettering is facing the bottom of the beaker.
8.  Change the sample rate to take one measurement each second.
9.  Begin data recording.
10.  Continue data recording for 2 minutes. Stop data recording and remove the sensor from the
beaker.
11.  Fill the 400-mL beaker nearly to the rim with cold tap water.
12.  Use tape to secure the relative humidity sensor on the rim of the beaker so the sensor
openings that contain the sensing elements are directly above the water. Make sure the
sensor is oriented "face down," so that the lettering is facing the water.
13.  Begin data recording. This will be your second run of data.
14. 
Continue data recording for 2 minutes. Stop data recording and remove the sensor from the
beaker.
Part 3 – Evaporation above warm water
15.  Empty the beaker and then fill it nearly to the rim with warm tap water.
16.  Secure the relative humidity sensor on the rim of the beaker with tape as before.
17.  Begin data recording. This is the third run of data.
18.  Continue data recording for 2 minutes. Stop data recording and remove the sensor. Note any
observations below.
________________________________________________________________________________________
Part 4 – Evaporation above ice
19.  Empty the beaker and then fill it nearly to the rim with ice.
20.  Secure the relative humidity sensor on the rim of the beaker with tape as before.
21.  Begin data recording. This is the fourth run of data.
22.  Continue data recording for 2 minutes. Stop data recording.
23.  Remove the relative humidity sensor from the beaker and set it aside.
24.  Observe the sides of the beaker. (You may want to use the hand lens for this observation.) Do
you see any droplets forming on the glass? Note any observations below.
________________________________________________________________________________________
Answering the Question
Analysis
1. How did your predictions in Part 1 compare to the results from Part 2?
________________________________________________________________________________________
________________________________________________________________________________________
2. Look back over your data. You may need to adjust the scale of the graph or look at different runs
of data. Your graphs show the relative humidity for the air over the cool water, over warm
water, over ice, and for the normal air. What do you notice about the relative humidity readings?
________________________________________________________________________________________
________________________________________________________________________________________
3. Based on what you have observed in this activity, would you expect the amount of water held in
the air to be greater near the equator where the ocean is warmer, or near the Arctic Circle where
the ocean is cooler? Why do you think this? Explain your reasoning.
________________________________________________________________________________________
________________________________________________________________________________________
4. Where do you think the water droplets on the beaker of ice are coming from?
________________________________________________________________________________________
________________________________________________________________________________________
5. What you have just seen—water coming out of the air—is called condensation. Can you think of
some examples in nature when condensation occurs?
________________________________________________________________________________________
________________________________________________________________________________________
6. Based on the evidence you have seen in this lab activity, what are the parts of the water cycle
that are invisible to our eyes? Describe them briefly and tell why you think this.
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
7. How did measuring relative humidity sensor help you to "see" evidence of where water is when it
appears invisible to your eyes?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Multiple Choice
Circle the best answer or completion to each of the questions or incomplete statements below.
1. Water vapor represents which phase or state of matter?
A. Liquid
B. Solid
C. Gas
2. When water boils in a pot on the stove, a misty steam rises above the pot and then disappears
into the air. The water has:
A. Been lost and will not be recovered by any means
B. Evaporated and undergone a process of the water cycle
C. Become separated into hydrogen and oxygen atoms
3. Which of the following is not a part of the water cycle?
A. Evaporation
B. Saturation
C. Condensation
4. About how much of the earth's water is immediately available for our use as fresh water?
A. About 70%
B. About 3%
C. Less than 3%
5. Which of the following best describes what happens to water that has evaporated from the
earth's surface?
A. Evaporated water is now lost to all future use, and diminishes the supply available to us.
B. Evaporated water remains locked in the atmosphere until winds carry it over the equator.
C. Evaporated water cools as it rises, and then condenses into rain or snow.
6. What evidence did you observe in this activity that water was evaporating from the beaker of
water?
A. The relative humidity, or amount of water vapor held in the air, increased near the
sensor.
B. The outside of the beaker tended to become the same temperature as the water or ice it
contained.
C. Water droplets formed on the outside of the beaker when it contained ice.
7. Suppose you had no access to fresh water, but you did have access to salty ocean water. What
parts of the water cycle could you use to produce fresh drinking water from the salt water?
A. It simply is not possible to obtain fresh drinking water from salty ocean water.
B. Boil the salty water to evaporate it, then capture the steam and cool it to condense it back
into liquid water that will now contain no salt
C. Freeze the salty water to make it solid ice, then chop and crush it into small pieces which
can easily be melted again, back into fresh water.
8. Which of the following places contain the earth's fresh water?
A. Oceans, lakes, and rivers
B. Lakes, rivers, underground rocks
C. Glaciers, polar ice caps, oceans
9. Which of the following best describes the water cycle?
A. Glaciers and polar ice caps melt, adding water to the oceans, which in turn provides
habitat for many species of living creatures.
B. Water particles can leave the water cycle at any time.
C. Water circulates continuously through the earth's crust, oceans, and atmosphere.
10. What happened to the water that was in the earth's oceans when the dinosaurs were alive?
A. That water continues to circulate through the water cycle today, and is still part of earth's
water.
B. That water disappeared from the earth at about the same time the dinosaurs did.
C. No one knows what happened to that water, because we were not there to observe it
directly.
Investigating Evaporation and Condensation in the Water Cycle
Purpose: To investigate evaporation and condensation of water. To determine
why some area of the world have more relative humidity than other areas.
Materials:
GLX or Spark
weather sensor
beaker or glass, 400 mL
hand lens or magnifying glass
cold water
warm water
cup filled with ice
tape
Directions:
Answer pre- activity questions and make predictions on your lab sheet.
Part 1: Evaporation above cold water
1. Connect the weather sensor to the data collection system using the extension
cord.
2. Display Relative Humidity on the y-axis of a graph with Time on the x-axis. See
quick guide for directions.
3. Place the weather sensor face down on top of an empty 400-mL beaker. Use
tape to secure the relative humidity sensor on the rim of the beaker so the
sensor openings that contain the sensing elements are directly over the
inside of the beaker. Make sure the sensor is oriented "face down," so that
the lettering is facing the bottom of the beaker.
4. Begin data recording.
5. Continue data recording for 2 minutes. Stop data recording and remove the
sensor from the beaker.
6. Fill the 400-mL beaker nearly to the rim with cold tap water.
7. Use tape to secure the relative humidity sensor on the rim of the beaker so the
sensor openings that contain the sensing elements are directly above the water.
8. See quick guide for instructions on how to set up data collection system for a
second data run.
9. Begin data recording.
10. Continue data recording for 2 minutes. Stop data recording and remove the
sensor from the beaker.
11. Sketch graphs on your lab sheet. Be sure to label each set of data or use
the key to be able to distinguish the different sets of data.
Part 2: Evaporation above warm water
1. Empty the beaker and then fill it nearly to the rim with warm tap water.
2. Secure the relative humidity sensor on the rim of the beaker with tape as
before.
3. Set up data collection system for a third run of data. See quick guide for
instructions.
4. Begin data recording.
5. Continue data recording for 2 minutes. Stop data recording and remove the
sensor.
6. Sketch the graph on your lab sheet. Be sure to label data set properly.
Part 3:
Evaporation above ice
1. Empty the beaker and then fill it nearly to the rim with ice.
2. Secure the relative humidity sensor on the rim of the beaker with tape as
before.
3. Set up data collection system for a fourth run of data. See quick guide for
instructions.
4. Begin data recording. This is the fourth run of data.
5. Continue data recording for 2 minutes. Stop data recording.
6. Remove the relative humidity sensor from the beaker and set it aside.
7. Observe the sides of the beaker. (You may want to use the hand lens for this
observation.) Write your observations on your lab sheet #2 question under
results.
8. Sketch graph on your lab sheet. Be sure to label the data set properly.
9. Finish answering the questions on your lab sheet.
Investigating Evaporation and Condensation in the Water Cycle
Lab Sheet
Pre-activity Questions:
1. List the places where water is found (for example, in a lake).
__________________________________________________________
___________________________________________________________
2. In your list, what places have water in the form of a liquid, solid (ice or
snow), or a vapor?
Sort your list above into the following categories.
Liquid: ______________________________________________________
Solid (ice): ___________________________________________________
Gas (vapor): __________________________________________________
3. You have looked at where water can be found on the earth and how much is
in various areas. How do you think water moves from place to place? Where
does water go? Get together with your group members and describe this
aspect of the water cycle.
___________________________________________________________
___________________________________________________________
___________________________________________________________
Predictions:
1. Will the relative humidity (percentage of water vapor) be higher above a dry
surface or one from which water is evaporating? Explain your reasoning.
2. How will the relative humidity above cold water compare to the relative
humidity above warm water?
3. Will the relative humidity above ice be higher or lower compared to the
relative humidity above cold or warm water?
Results:
Sketch the graph of your results. Draw each line with a different color so you can
distinguish between the different sets of data.
Relative Humidity of Different Temperatures of air
Relative Humidity (%)
Normal air
Air above cold water
Air above warm water
Air above ice
0
20
40
60
80
100
120
Time (s)
1. Write a description of what the graph is describing about relative humidity.
___________________________________________________________
_________________________________________________________
___________________________________________________________
___________________________________________________________
2. Write observations about what you see forming on the outside of the glass
with ice. Where do you think these water droplets are coming from?
___________________________________________________________
___________________________________________________________
3. What you have just seen—water coming out of the air—is called condensation.
Can you think of some examples in nature when condensation occurs?
___________________________________________________________
___________________________________________________________
4. Based on the evidence you have seen in this lab activity, what are the parts of
the water cycle that are invisible to our eyes? Describe them briefly and tell
why you think this.
___________________________________________________________
___________________________________________________________
___________________________________________________________
5. How did measuring relative humidity sensor help you to "see" evidence of where
water is when it appears invisible to your eyes?
___________________________________________________________
___________________________________________________________
6. Based on what you have observed in this activity, would you expect the amount
of water held in the air to be greater near the equator where the ocean is warmer,
or near the Arctic Circle where the ocean is cooler? Why do you think this? Explain
your reasoning.
___________________________________________________________
___________________________________________________________
Water's Role in Our Climate
(Pasco lab activity)
GLEs
3rd Grade: SI 1-12; ESS 48, 54, 55
4th Grade: 1-13; ESS 57, 58
Correspondence to Textbook Activities
3rd Grade: Unit 8 p. 355; p. 359
4th Grade: Unit 6 p. 323; p. 329
Question
Do the oceans protect us from sudden changes in temperature?
Materials and Equipment
For each student or group:
 GLX or Spark
 Teaspoon
 Temperature sensors
 Dry sand, 1000 mL (4 cups)
 Small cup for water, 50-mL
 Table salt, 2 teaspoons
 Plastic food storage containers with lids
 Water, 100 mL
 100-W lamp
Safety
Add this important safety precaution to your normal laboratory procedures:

Do not look directly at the sun or 100-W lamp. Permanent damage to your eyes may result.
Teacher Notes:
Students will need to have 2 experimental set-ups (one with salt water and one without salt water).
Divide the class into 2 groups or if the class is large, have multiple groups working of each set-up.
You may want to divide the directions in two so that each group sees only its instructions.
Thinking about the Question (Read aloud and discuss with students.
A photograph of a beach may enhance the discussion.)
Water changes temperature very slowly. This resistance to sudden changes in temperature makes
water an excellent place for organisms to live. Changes in water temperature occur very gradually
and seasonal changes are small compared to those on land.
Discuss with your lab group members how oceans moderate the earth’s climate.
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Investigating the Question
Part 1 – Making predictions
1.  Think about a sandy shoreline next to an ocean. How does the presence of the water affect
the temperature of the shoreline?
________________________________________________________________________________________
________________________________________________________________________________________
2.  Predict what the difference in temperature would be without the ocean present. Explain your
reasoning. Be prepared to share your prediction with the class.
________________________________________________________________________________________
________________________________________________________________________________________
Part 2 – Modeling land and coastline
3.  Obtain a plastic food storage container with a clear lid from your teacher. The containers
should have a hole punched through their sides that will allow a temperature sensor to slip
through the side of the container.
4.  Start a new experiment on the data collection system.
5.  Connect a temperature sensor to the data collection system.
6.  Monitor live data to measure the temperature of the air in the location where you will be
conducting your experiment. Record the temperature in the space below:
Air temperature =
degrees Celsius
7.  Display a graph with temperature on the y-axis and time on the x-axis.
8.  One Group of Students: Place the temperature sensor through the side of one of the
containers so that the tip of the sensor is placed entirely inside the container. Fill the
container approximately half full with sand so that the temperature sensor is completely
covered with sand.
9.  Attach the lid to the container.
10.  Second Group of Students: Place the temperature sensor through the side of the container so
that the tip of the sensor is placed entirely inside the container. Fill the container
approximately half full with sand so that the temperature sensor is completely covered with
sand.
11.  Obtain a small cup from your teacher. Place 1 teaspoon of table salt and 50 mL of tap water
into the cup. Stir the water in the cup until all of the salt is dissolved.
12.  Place the small cup of salt water in the container, pressing it down into the sand if necessary
so it will fit when the lid of the container is closed.
13.  Attach the lid to the container.
Part 3 – Measuring temperature changes
14.  Place the container outside in warm overhead sunshine. If sunlight is not available, use a
100 W lamp approximately 1/2 meter above the containers.
15.  Start data recording on the temperature sensor. Continue collection for 10 minutes. You will
enter your temperature data in a table below; you may write this data as it is being recorded,
or you may wait until the end of data collection.
16.  After 10 minutes, stop data recording.
17.  Complete Table 1 below, if you have not done so already.
Table 1: Temperatures 1 and 2
Time
(minutes)
Temperature 1 (˙C)
(Sand only)
Temperature 2 (˙C)
(Sand and salt water)
1
2
3
4
5
6
7
8
9
10
Answering the Question
Analysis
1. How did the temperatures of the sand in each container compare with the temperature outside
the containers?
________________________________________________________________________________________
2. How does the temperature of the sand in the sand-only container compare to the temperature of
the sand inside the other container that has water and sand? Did the container with only sand
heat up faster?
________________________________________________________________________________________
3. How did the presence of salt water in one container affect the temperature? Be prepared to share
your answer with the class.
________________________________________________________________________________________
4. Did the water in the container prevent major temperature changes in the sand? Explain your
thinking.
________________________________________________________________________________________
________________________________________________________________________________________
True or False

Enter a "T" if the statement is true or an "F" if it is false.
_____________ 1. Water, which covers the majority of the earth's surface, circulates through the
crust, oceans, and atmosphere in what is known as the "water cycle."
_____________ 2. A large portion of the earth's surface is covered with water.
_____________ 3. Water has the property of being able to resist sudden changes in its temperature.
_____________ 4. Oceans have no effect on temperature.
_____________ 5. Breezes blow near the shore of oceans because of differences in temperature over
the land and over the water.
_____________ 6. During the night, the beaches cool more slowly than the ocean waters.
_____________ 7. Seasonal changes in the ocean are smaller than seasonal changes on land.
Key Term Challenge

Fill in the blanks from the randomly ordered words below. You may change the form of a word, for
example by making a singular word plural. You may not use every word, and you may use a word more than
once:
gains
energy
sun
shore
loses
sand
temperatures
water
oceans
70%
glacier
polar ice caps
1. Water
energy by absorbing it from the
during the
day.
2. Sand
3. Earth's
energy more quickly than water does.
help our planet maintain stable
that remain
within limits.
4. Almost all of the
on Earth comes from the
5. Much of our fresh
is stored in the solid form in the
.
Water's Role in Our Climate
Purpose: To determine how oceans protect us from sudden changes in
temperature.
Materials:
Group A:
GLX or Spark
Temperature sensor
Plastic food storage container with lid
Dry sand
Group B:
GLX or Spark
Temperature sensor
Plastic food storage container with lid
Small cup for water
Water
Dry sand
Table salt
Spoon
Group A – Modeling land
1. Obtain a plastic food storage container with a clear lid from your teacher. The
containers should have a hole punched through their sides that will allow a
temperature sensor to slip through the side of the container.
2. Start a new experiment on the data collection system.
3. Connect a temperature sensor to the data collection system.
4. Monitor live data to measure the temperature of the air in the location where
you will be conducting your experiment. Record the temperature on your lab
sheet.
5. Display a data table which measures temperature changes over time. See Quick
Guide for instructions.
6. Place the temperature sensor through the side of one of the containers so that
the tip of the sensor is placed entirely inside the container. Fill the
container approximately half full with sand so that the temperature sensor
is completely covered with sand.
7. Attach the lid to the container.
8. Place the container outside in warm overhead sunshine. If sunlight is not
available, use a 100 W lamp approximately 1/2 meter above the containers.
9. Start data recording on the temperature sensor. Continue collection for 10
minutes. You will enter your temperature data in a table below; you may write
this data as it is being recorded, or you may wait until the end of data
collection.
10. After 10 minutes, stop data recording.
11. Complete Table 1 on your lab sheet. Share your data with your buddy group so
that you have both sets of data.
Group B: Modeling shoreline
1. Obtain a plastic food storage container with a clear lid from your teacher. The
containers should have a hole punched through their sides that will allow a
temperature sensor to slip through the side of the container.
2. Start a new experiment on the data collection system.
3. Connect a temperature sensor to the data collection system.
4. Monitor live data to measure the temperature of the air in the location where
you will be conducting your experiment. Record the temperature on your lab
sheet.
5. Display a data table which measures temperature changes over time. See Quick
Guide for instructions.
6. Place the temperature sensor through the side of the container so that the tip
of the sensor is placed entirely inside the container. Fill the container
approximately half full with sand so that the temperature sensor is
completely covered with sand.
7. Obtain a small cup from your teacher. Place 1 teaspoon of table salt and 50 mL
of tap water into the cup. Stir the water in the cup until all of the salt is
dissolved.
8. Place the small cup of salt water in the container, pressing it down into the sand
if necessary so it will fit when the lid of the container is closed.
9. Attach the lid to the container.
10. Place the container outside in warm overhead sunshine. If sunlight is not
available, use a 100 W lamp approximately 1/2 meter above the containers.
11. Start data recording on the temperature sensor. Continue collection for 10
minutes.
12. After 10 minutes, stop data recording.
13. Complete Table 1 on your lab sheet. Share your data with your buddy group so
that you have both sets of data.
Water's Role in Our Climate
Lab Sheet
Prediction:
Will there be a difference in temperature between the land without water present
and the land with water present? Explain your reasoning.
______________________________________________________________
______________________________________________________________
_____________________________________________________
Results:
Air temperature =
degrees Celsius
Temperatures of Land with or without Water Present
Time
(minutes)
1
2
3
4
5
6
7
8
9
10
Temperature 1
(˙C) (Sand only)
Temperature 2 (˙C)
(Sand and salt
water)
Questions:
1. How did the temperatures of the sand in each container compare with the
temperature outside the containers?
___________________________________________________________
2. How does the temperature of the sand in the sand-only container compare to
the temperature of the sand inside the other container that has water and
sand? Did the container with only sand heat up faster?
___________________________________________________________
3. How did the presence of salt water in one container affect the temperature?
_________________________________________________________
4. Did the water in the container prevent major temperature changes in the sand?
Explain your thinking.
___________________________________________________________
___________________________________________________________
5. Think about a sandy shoreline next to an ocean. How does the presence of the
water affect the temperature of the shoreline?
___________________________________________________________
___________________________________________________________
Conclusion statement:
Water changes temperature very slowly. This resistance to sudden changes in
temperature makes water an excellent place for organisms to live. Changes in water
temperature occur very gradually and seasonal changes are small compared to
those on land.
Discuss with your lab group members how oceans moderate the earth’s climate.
___________________________________________________________
___________________________________________________________
___________________________________________________________
Weather Tracking
Objective:
Students will use weather instruments to measure air pressure, wind speed,
humidity, amount of liquid precipitation, and temperature. Students can use the
instruments to predict the areas weather. Students will also interpret weather
graphs and maps to determine weather patterns in United States.
Materials:
Optional: Pasco weather station sensor
Barometer
Anemometer
Hygrometer
Water gauge
Outdoor thermometer
Internet access
Handouts
Poster paper (hang on wall)
Overview:
Students will measure air pressure, wind speed, humidity, amount of liquid
precipitation, and temperature over several weeks to determine their local
weather. At the same time, students will record these same measurements from
weather maps for state capitals in selected states. At the end of several weeks
students can create graphs from their data or their own weather maps. From the
graphs or weather maps the students will discover weather patterns.
Background:
Barometer
A barometer measures air pressure: A "rising" barometer indicates increasing air
pressure; a "falling" barometer indicates decreasing air pressure.
In space, there is a nearly complete vacuum so the air pressure is zero. On Earth, because
there are many miles of air molecules stacked up and exerting pressure due to the force
of gravity, the pressure is about 14.7 pounds per square inch at sea level.
The interesting thing about air pressure is that it is different at different points on the
planet and it changes over time. On any given day you would expect the air over a desert to
have a lower pressure than the air over an ice cap. And that would be true. This same sort
of pressure differences occur all over the planet for various reasons.
These pressure differences have a big effect on the weather, so if you know the current
air pressure at your house, as well as the pressure trend, you are able to predict certain
things about the weather. As a very loose rule, a high-pressure area will be clear, and a
low-pressure area will be cloudy and rainy.
Anemometer
An anemometer is a common weather instrument used to measure the speed of the wind.
There are several types of anemometers, ranging in complexity; the most basic models
measure the wind speed, or more complex ones can measure wind speed, wind direction and
wind pressure.
The spinning cup anemometer measures wind speed only. It is the most common type of
anemometer and is also the most basic model. The cup anemometer consists of three or
four cups (one with a magnet attached to it) positioned on a 45 degree angle and mounted
to a vertical pole. As the wind blows, it catches in the hollow of one or more of the cups,
and forces the anemometer to spin on the pole. Each time the anemometer completes a full
rotation, the magnet on the cup is detected by a reed switch, triggering an output pulse
proportionate to the wind speed. The number of pulses is counted over a period of time,
and converted into an average wind speed that is recorded on a display or weather station.
The biggest thing we will often notice about the wind is the wind chill factor, which
determines how cold we feel when we are outside. The wind chill temperature is always
equal to or below the air temperature.
Our bodies maintain our internal temperature at around 98.6oF and we are most
comfortable when the air temperature is between 60 and 80oF. In these temperatures, our
skin temperature is around 90oF because the excess heat from our bodies leaves to help
cool our skin. If wind is blowing past our skin, more heat escapes into the environment
reducing the skin temperature further and we feel colder.
Hygrometer
Relative humidity can be measured by an instrument called a hygrometer. The simplest
hygrometer - a sling psychrometer - consists of two thermometers mounted together with
a handle attached on a chain. One thermometer is ordinary. The other has a cloth wick
over its bulb and is called a wet-bulb thermometer.
When a reading is to be taken, the wick is first dipped in water and then the instrument is
whirled around. During the whirling, the water evaporates from the wick, cooling the wetbulb thermometer. Then the temperatures of both thermometers are read.
If the surrounding air is dry, more moisture evaporates from the wick, cooling the wetbulb thermometer more so there is a greater difference between the temperatures of the
two thermometers. If the surrounding air is holding as much moisture as possible - if the
relative humidity is 100% - there is no difference between the two temperatures.
Meteorologists have worked out charts of these differences for each degree of
temperature so that the observer can find relative humidity easily.
Heat Index
The heat index (HI) is an index that combines air temperature and relative humidity in an
attempt to determine the human-perceived equivalent temperature — how hot it feels,
termed the felt air temperature. The human body normally cools itself by perspiration, or
sweating, which evaporates and carries heat away from the body. However, when the
relative humidity is high, the evaporation rate is reduced, so heat is removed from the
body at a lower rate causing it to retain more heat than it would in dry air.
At high temperatures, the level of relative humidity needed to make the heat index higher
than the actual temperature is lower than at cooler temperatures. For example, at
approximately 27 °C (80 °F), the heat index will agree with the actual temperature if the
relative humidity is 45%, but at about 43°C (110°F), any relative-humidity reading above
17% will make the Heat Index higher than 43°C (110 °F).
The heat index is calculated only if the actual temperature is above 27 °C (80 °F), dew
point temperatures greater than 12 °C (54 °F), and relative humidities higher than
40%.The heat index and humidex figures are based on temperature measurements taken in
the shade and not the sun, so extra care must be taken while in the sun.
The table below shows the symbols used on the latest U.S. surface chart (weather map)
Understanding surface charge symbols and
the systems they show
Low pressure area
High pressure area
Warm front
Cold front
Occluded front
Stationary front
Trough
Low Pressure
When forecasters say a low pressure area or
storm is moving toward your region, this
usually means cloudy weather and
precipitation are on the way. Low pressure
systems have different intensities with some
producing a gentle rain while others produce
hurricane force winds and a massive deluge.
The centers of all storms are areas of low air
pressure.
Air rises near low pressure areas. As air rises,
it cools and often condenses into clouds and
precipitation.
If the low pressure area is the center of a Northern Hemisphere extra tropical storm, a
steady rain or snow can fall to the north of the warm front as warm moist air from the
south rises up and over the cold air ahead of the warm front. Showers and thunderstorms
often fire up ahead of the cold front in the warm, unstable air. Usually, showers and
thunderstorms ahead of the cold front don't last as long as the precipitation ahead of the
warm front.
Due to the counterclockwise circulation around low pressure areas in the Northern
Hemisphere, cold air will likely be found to the north and west of low pressure areas while
warm air is most often found to the south and east of low pressure areas.
High Pressure
Often, you hear a weather forecaster say that an area of high pressure will dominate the
weather. This usually means your region has several partly to mostly sunny days in store
with little or no precipitation. Air tends to sink near high-pressure centers, which inhibits
precipitation and cloud formation. This is why high-pressure systems tend to bring bright,
sunny days with calm weather.
Air flows clockwise around a high-pressure system in the northern hemisphere. As a
result, regions to the east of a high-pressure center often have northerly winds bringing in
relatively cold air while regions to the west have southerly winds bringing in relatively
warm air.
Sometimes, high-pressure systems stall over a particular region for long periods of time
and bring several days of sunny, calm weather with little or no precipitation. High pressure
systems usually form where the air converges aloft. As the air converges in the upperlevels of the atmosphere, it forms an area of higher pressure and is forced to sink. The
sinking air spirals outward, clockwise in the Northern Hemisphere, counterclockwise south
of the Equator. High pressure systems are steered by upper-level winds much the same
way low pressure systems are steered.
Warm Front
The term "warm front" sounds like something you'd like to have coming your way on a cold
winter's day. Think again. A warm front is the boundary between warm and cool, or cold,
air when the warm air is replacing the cold air. That sounds like what you want. However,
warm fronts often bring days of inclement weather.
Warm fronts often form to the east of low pressure centers, where southerly winds push
warm air northward. As the warm air advances northward it rides over the cold air ahead
of it, which is heavier. As the warm air rises the water vapor in it condenses into clouds
that can produce rain, snow, sleet or freezing rain, often all four.
The warm front symbol on a weather map marks the warm-cold boundary at the earth's
surface. The circles on the red line point in the direction the warm air is moving. As you
move into the cold air the warm-cold boundary is overhead. The boundary, along with
clouds and precipitation, can stretch hundreds of miles over the cold air. This is why a
slow-moving warm front can mean hours, if not days, of cloudy, wet weather before the
warm air finally arrives. Since warm air is lighter and less dense than cold air, the cold air
ahead of a warm front at the surface must retreat before warm air can move in.
Sometimes, cold air is very stubborn and hard to move, which slows the warm front down
and can lead to several days of wet weather. This happens often during winter along the
East Coast as cold air banks up against the Appalachian Mountains. It is commonly
referred to as cold air damming.
Cold Front
The term "cold front" is one of meteorology's most misused terms. Many people say "cold
front" when they are really talking about the mass of cold air that moves in behind the
front. In weather, all fronts are boundaries between masses of air with different
densities, usually caused by temperature differences. A cold front is a warm-cold air
boundary with the colder air replacing the warmer.
While a winter cold front can bring frigid air, summer cold fronts often can more
accurately be called "dry" fronts. As anyone who's ever suffered through a few days of
hot, humid air anywhere east of the Rockies can tell you, cold fronts are welcome visitors
because they often bring air that might be only a few degrees cooler, but much less humid.
The weather map symbol for a cold front is a blue line with triangles pointing the direction
the cold air is moving. As a cold front moves into an area, the heavier, cool air pushes
under the lighter, warm air it's replacing. The warm air cools as it rises. If the rising air is
humid enough, water vapor in it will condense into clouds and maybe precipitation.
In the summer, an arriving cold front can trigger thunderstorms, sometimes severe
thunderstorms with large hail, dangerous winds and even tornadoes. As a cold front arrives
in a particular place, the barometric pressure will fall and then rise. Winds ahead of a cold
front tend to be from a southerly direction while those behind the front - in the cooler air
- tend to be northerly. In fact, weather stations use the shift from a southerly to a
northerly wind direction as the indication that a cold front has passed the station.
Occluded Front
Often, in the later stages of a storm's life cycle, a frontal occlusion occurs. This happens
when the air in the warm sector of the storm is lifted off the ground.
This can happen in two ways:
 A cold occlusion, which occurs when the air behind the front is colder than the air
ahead of the front. In this situation, the coldest air undercuts the cool air ahead of
the front and the occluded front acts very similar to a cold front.
 A warm occlusion, which occurs when the air behind the front is warmer than the
air ahead of the front. In this situation, the cool air is lighter than the coldest air
ahead of the front. As a result, the cool air rises up and over the coldest air at the
surface and the occluded front acts very similar to a warm front.
In both types of occlusions, the occluded front has well defined vertical boundaries
between the coldest air, the cool air, and the warm air. Many weather textbooks state
that occluded fronts occur when the cold front catches up with and overtakes the warm
front, but many scientists disagree. They say that frontal occlusions occur when storms
redevelop farther back into the cold air. In most cases, storms begin to weaken after a
frontal occlusion occurs.
Stationary Front
A cold front is the boundary between cool and warm air when the cool air is replacing the
warm air. A warm front is the boundary when the warm air is winning the battle. When the
pushing is a standoff, the boundary is known as a stationary front. Stationary fronts often
bring several days of cloudy, wet weather that can last a week or more.
Since neither the warm air nor the cold air is advancing, the stationary front weather map
symbols combine both the cold front and the warm front symbols. Maps show stationary
fronts with alternating triangles pointing away from the cold air and half circles pointing
away from the warm air. Color maps alternate the cold front blue and warm front red.
A weather map's frontal position shows where the boundary touches the Earth. The
boundary can be thousands of feet above the ground a couple of hundred miles away from
the surface front. If there's enough humidity in the air, clouds and precipitation will form
as warm air overruns cool air along a stationary front. Sometimes, stationary fronts can
stay stationary or nearly so for days. When this happens, the sky can stay gray with rain
or snow. Stationary fronts are also good places for new low pressure areas to begin and
grow into storms.
Trough
A trough is an elongated area of low atmospheric pressure that can occur either at the
Earth's surface or at higher altitudes. Upper-level troughs influence many surface
weather features, including the formation and movement of surface low pressure areas
and the locations of clouds and precipitation. Precipitation tends to fall to the east of the
trough axis while colder, drier air tends to prevail to the west of the trough. This happens
because air rises to the east of troughs. As air rises, it cools, and its humidity begins
condensing into clouds and precipitation. Air sinks on the west side of troughs, which
inhibits clouds and precipitation.
On weather maps of the Northern Hemisphere, troughs are shown by upper-air winds, or
jet streams, blowing south and then turning back to the north. Strong upper-level troughs
can be become negatively tilted and are associated with Arctic outbreaks and major
snowstorms during winter. Surface low pressure areas tend to develop to the east of
upper-level troughs in the rising air.
Weather Tracking
(student sheet)
Purpose: To use weather maps and weather instruments to track the weather over
several weeks.
Your Job: Each group will be responsible for tracking the weather for an assigned
state using weather maps from the internet. Each group will also use weather
instruments to measure local weather at your school.
Internet Weather map directions:
1. Go to website: http://usatoday.com
2. Click on the orange weather link at the top of the web page.
3. Above the weather maps- Find a Forecast: type in City, State
4. Record readings: average temperature, barometer reading, humidity,
heat index, wind direction, wind speed, and is your area- cloudy, sunny, or having
thunderstorms,
5. Click on maps-current weather-fronts
6. Read the map to determine if your state is in a high pressure area (H) or a low
pressure area (L).
7. Use the key below the map to determine what type of front(if any) is above
your state.
Local Weather Directions:
1. Use the weather /anemometer sensor on spark or GLX to measure the local
Weather or other weather measuring instruments (barometer, anemometer,
hygrometer, thermometer and rain gauge)
2. Record readings in your journal: wind speed, temperature, relative humidity,
barometric pressure, heat index
Weather Tracking
(student sheet)
Make two charts in your journal on separate pages: One for the city you live in and
one for your group’s assigned state.
An X is placed on the measurements that will be taken by you at your local school
with the weather measurement tools.
City, State: __________________________________
Dates
Current
Temperature
X
High
Temp.
and
Low Temp.
Relative
Humidity
X
Heat
Index
Barometer
Pressure
(# and
Rising or
lowering)
Wind
Direction
and
Wind Speed
X
X
Low
Pressure
Area
Or
High
Pressure
Area
Type
of
Front
Cloudy
Sunny
or
Amount of
Liquid
Precipitation
Thunderstorms
X
Weather Comparison
(student sheet)
Procedure: Walk around the room and examine the weather charts from states all
over the United States including the data you collected from your school. Using
the weather data collected, answer the following questions.
1. What types of measurements can help us determine the type of weather that
we will have?
2. What measurement tool was used to measure the pressure data you collected?
What measurement tool was used to measure the humidity in the air?
What measurement tool was used to measure the temperature data you
collected?
What measurement tool could you used to measure amount of precipitation
(rainfall) in each state instead of reporting the percentage of precipitation ?
3. Is the weather the same in all states in United States?
4. Is Louisiana having a rainy or dry summer? What type of measurement did
you collect to answer this question?
5. Pressure: Is there a relationship between higher pressure numbers or high
pressure areas and sunny weather? Explain your answer.
6. Pressure: Is there a relationship between lower pressure numbers or low
pressure areas and cloudiness/rain? Explain your answer.
7. Temperature: What season is United States experiencing? How do we know
this?
8. Based on your answer to question number 7, what type of precipitation (rain or
snow) would you expect united states to have this season? Explain your answer.
9. Temperature: Is there a difference in overall temperature between the
northern states and the southern states? Explain your answer.
10. Humidity: Which state has the lowest amount of relative humidity? What
type of ecosystem would this state have that contributes to the low relative
humidity?
11. Humidity: Which states have more humidity- states on the coast or states
more inland?
12. Humidity: Is there a difference in overall humidity between the
northern states and the southern states? Explain your answer.
13. Heat Index: Look at the states with temperatures higher than 27 degrees
Celsius (80 degrees Fahrenheit) with a relative humidity above 40%.
Which temperature is higher heat index reading or the air temperature
reading?
14. Heat Index: Look at the states with temperatures higher than 27 degrees
Celsius (80 degrees Fahrenheit) with a relative humidity above 40%. What
happens to the heat index as humidity and temperature increase?
Natural Disasters
Objective:
Students will learn how different natural disasters form, how do meteorologist
predict and study disasters and the damage each disaster may cause.
Materials:
Internet
Handouts
PowerPoint/flipchart
Background:
Lighting storms
Winter storms
Tornadoes
Hurricanes
Tsunamis
Floods
Wildfires
Volcanoes
Earthquakes
Overview:
1. Assign students into 9 groups.
2. Using the PowerPoint/flipchart, have one person from each group choose
their natural disaster that they will research.
3. Students will answer basic questions about their assigned natural disaster
through a web quest.
4. Each group will develop a poster to show what they learned about the natural
disaster.
5. Once posters are complete, one person from each group will choose a
character and a location for their news broadcast.
Natural Disasters Web quest
(student sheet)
Goal: To research basic facts about selected Natural Disasters.
Your group will then make a poster to teach the class about the
assigned natural disaster.
Suggested Websites:
http://news.bbc.co.uk/2/hi/science/nature/7533909.stm
http://environment.nationalgeographic.com/environment/natural-disasters/
http://www.weatherwizkids.com/
http://www.usatoday.com/life/graphics/natural_disasters/flash.htm
http://www.fema.gov/kids/dizarea.htm
In your journals, answer the following questions for your assigned
natural disasters: floods, hurricanes, tornadoes, tsunamis,
thunder/lightning storms, winter storms, volcanoes, earthquakes,
wildfires
Questions to answer about your natural disasters:
1. Describe the natural disaster. How does it form? What weather conditions are
present? How does it move or acquire energy?
2. Where do they typically form? In what season does it normally occur? Why is
this area a good place for this type of disaster?
3. Can it be predicted? If so, how? (Technology used to detect/predict for
example: radar, weather balloons, satellites) If not, why?
4. What kind of damage does it cause?
5. What should you do if this happens? Where is the safest place to be?
Natural Disaster News Broadcast
(student sheet)
Goal:
Using the information from your web quest you are to design a news
broadcast to teach the other students about your natural disaster.
RULES:
1. Must use the character and location that you randomly picked.
2. Must include some information from each of the questions from
your web quest.
3. Have fun and be as creative as you would like.
4. You may use props that are appropriate for your news broadcast.