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The
Reasons for the Seasons
Lesson
Plan
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Summary: The
Reasons for the Seasons is actually three activities in one. In Do
Shadows Change with the Seasons?, students conduct a controlled investigation
to determine the length of the sun's shadow on a fixed object (i.e., flagpole,
telephone pole, etc.) over a three-day period (one day in the fall, one in the
winter, and one in the spring). This concrete experience acts as a springboard
to the abstract understanding of the positioning of the sun and Earth as it relates
to the changing seasons. In How Do Sunrise and Sunset
Change with the Seasons?, students plot sunrise and sunset data collected
from the first day of fall, winter, and spring in order to analyze seasonal patterns.
In What Can a Model of the Earth and Sun Tell Us about the Seasons?, the
teacher uses a lamp and globe to reinforce the connection between the Earth's
tilt, its revolution, and seasonal change. The
Family Page extends this learning to the community
by providing families with challenges to explore at home.
Day 1:
Do Shadows Change with the Seasons?--Fall Shadow Observation (45 min.)
Note: Begin this portion of the lesson on a sunny day on or near the
first day of fall.
Ready...
- Gather local
sunrise/sunset data for the day from the local newspaper or the Internet.
- Gather the
following materials:
- 25 or 50 meter
tape measure (or other metric equivalent)
- compass
- Copy a class
set of the Thinksheet and Data Sheet.
- Make overhead
transparencies of the Thinksheet and Data Sheet.
- Select a fixed
object (i.e., flagpole, telephone pole, etc.) with a clear area to the north
to allow for shadow measurement.
Get Set...
- Introduce The
Reasons for the Seasons investigation to your students. "In
this activity you will..."
- investigate what
causes the seasons to change
- hypothesize whether
shadows change with the seasons
- Tell students
what behaviors you expect of them before, during, and after the lesson.
- scientific thinking
- respectful listening
- speaking in appropriate
voices
- participating
- Explain how
today's lesson is grouped:
- a whole class
introduction
- an outdoor activity
- a whole class
discussion
- Group students
into teams of four. Then ask the members of each team to number from
one to four.
- Students share
what they know about the seasons with the class.
- Introduce the
Thinksheet.
- Students record
notes in the "Think it Through" section of their Thinksheet.
- Have students
record their team number (1-4) on the Thinksheet.
- Give students three
minutes to complete the chart in the "Think It Through" section
of the Thinksheet.
- Students Think/Pair/Share
their notes.
- Think:
Reread responses silently.
- Pair: Share
responses with a partner.
- Share: Discuss
responses as a class.
Go!!!
- Outdoor Investigation
- Go out to the
pole where the shadow will be measured.
- Have one of the
student teams measure the flagpole shadow to the nearest tenth of a meter.
- Ask the "number
1" student in each group to verify the measurement.
- Using a compass,
record the shadow direction in degrees (e.g., 350 degrees N/NW) so that
you can have the exact location for comparison during December and March
observations.
If you have six to eight compasses, have teams do this. Note: If a compass
is not available, you will need to find a way to permanently mark the
location of the shadow.
- Ask students to
hypothesize the length of the shadow around the first day of winter by
standing where they predict the end of the shadow will be.
- Direct students
to describe their hypothesis location in words on the back of either their
Thinksheet or Data Sheet (e.g., by the fire hydrant, three large steps
toward the road from the parking sign, five meters north of the...).
- Back Inside
- Pass out and complete
Data Sheet.
- Students record
their hypothesis for December on the Thinksheet.
- Point out the variables
listed on the Thinksheet (page 2) that will
help this investigation to be successful.
- Collect and file
Thinksheets and Data Sheets until December.
- Distribute
the Family Page.
Day 2:
Do Shadows Change with the Seasons?--Winter Shadow Observation (30 min.)
Note:
Begin this portion of the lesson on a sunny day on or near the first day of
winter.
Ready...
- Gather local
sunrise/sunset data for the day from the local newspaper or the Internet.
- Gather the
following materials:
- 25 or 50 meter
tape measure (or other metric equivalent)
- compass
- flashlight and
flagpole image
- Locate the
class set of Seasons Thinksheets and Data Sheets.
- Locate Thinksheet
and Data Sheet overhead transparencies.
Get Set...
- Explain
how today's lesson is grouped and set expectations for behavior.
- Redistribute
Thinksheets and Data Sheets to students.
- Reread the
completed Data Sheet and Thinksheet information from the fall. Make sure
students notice their student number.
- Point out
the Variables and Procedure on the back of the Thinksheet.
Go!!!
- Outdoor Investigation
- Go out to the pole
where the shadow will be measured. Note: Since this is a controlled
experiment, it is important to measure the shadow at the same time as
in the fall. Because Daylight Savings Time (DST) has begun since
the fall observation, measurements should be taken one hour earlier.
- Point out the location
of the shadow during the fall observation.
- Have students stand
where they hypothesized the shadow to be.
- Have one of the
student teams measure the flagpole shadow to the nearest tenth of a meter.
Tip: Sunny days in December can be scarce. It is possible
to mark the shadow position on a cloudy day (if the sun can be seen through
the clouds) by positioning your view of the sun so that it is "sitting"
on the top of the pole. Caution students to never look directly at the
sun.
- Ask the "number
2" student in each group to verify the measurement.
- Using a compass,
record the shadow direction in degrees (e.g., 350 degrees N/NW) so that
you can have the exact location for comparison during the March observation.
Note: If a compass is not available, you will need to find a way to permanently
mark the location of the shadow.
- Ask students to
hypothesize the length of the shadow for the first day of spring by standing
where they predict the end of the shadow will be.
- Direct students
to describe their hypothesis location in words on the back of either their
Thinksheet or Data Sheet (e.g., by the fire hydrant, three large steps
toward the road from the parking sign, five meters north of the...).
- Back Inside
- Use a flashlight
and a flagpole image to demonstrate the reason for a longer shadow in
the winter. (The sun is positioned lower in the sky at the same time
of day.)
Leave this as a
classroom center for a few days so that students can manipulate it.
- Pass out and complete
Data Sheet. (Future example)
- Students record
their hypothesis for March on the Thinksheet.
- Collect and file
Thinksheets and Data Sheets until March.
- Distribute
another copy of The Reasons for the Seasons Family
Page.
Day 3:
Do Shadows Change with the Seasons?--Spring Shadow Observation (30 min.)
Note:
Begin this portion of the lesson on a sunny day on or near the first day of
spring.
Ready...
- Gather local
sunrise/sunset data for the day from the local newspaper or the Internet.
- Gather the
following materials:
- 25 or 50 meter
tape measure (or other metric equivalent)
- compass
- flashlight and
flagpole image
- Locate the
class set of Seasons Thinksheets and Data Sheets.
- Locate Thinksheet
and Data Sheet overhead transparencies.
Get Set...
- Explain how
today's lesson is grouped and set expectations for behavior.
- Redistribute
Thinksheets and Data Sheets to students.
- Reread the
completed Data Sheet and Thinksheet information from the fall and winter.
Make sure students notice their student number.
- Point out
the Variables and Procedure on the back of the Thinksheet.
Go!!!
- Outdoor Investigation
- Go out to the pole
where the shadow will be measured.
Note: Since this is a controlled experiment, it is important to
measure the shadow at the same time at each season. Because Daylight
Savings Time (DST) has begun since the fall observation, measurements
should be taken one hour earlier (same time as in December).
- Point out the location
of the shadow for the fall and winter observations.
- Have students stand
where they hypothesized the shadow to be.
- Have one of the
student teams measure the flagpole shadow to the nearest tenth of a meter.
- Ask the "number
3" student in each group to verify the measurement.
- Using a compass,
record the shadow direction in degrees (e.g., 350 degrees N/NW) so that
you can have the exact location for comparison to the other observations.
Note: If a compass is not available, you will need to find a way to permanently
mark the location of the shadow.
- Ask students to
hypothesize the length of the shadow for the first day of summer by standing
where they predict the end of the shadow will be.
- Direct students
to describe their hypothesis location in words on the back of either their
Thinksheet or Data Sheet (e.g., by the fire hydrant, three large steps
toward the road from the parking sign, five meters north of the...).
- Back Inside
- Use a flashlight
and a flagpole image to demonstrate the reason for a shorter shadow
in the spring than in the winter (i.e., The sun is positioned higher
in the sky at the same time of day.)
Leave this as a
classroom center for a few days so that students can manipulate it.
- Pass out and complete
Data Sheet. (Future example)
- Discuss and record
patterns in the data on the Data Sheet.
- Students record
their hypothesis for June on the Thinksheet.
Day 4:
How Do Sunrise and Sunset Change with the Seasons? (30 min.)
Ready...
Get Set...
- Distribute
the Sunrise/Sunset Data Sheet.
- Plot Standard
sunrise data for fall, winter, and spring and connect the dots.
- Plot Standard
sunset data for fall, winter, and spring and connect the dots.
- Calculate hours
of daylight and record. (Click to see an
example with the above steps completed.)
Go!!!
- Discuss the
difference between an observation and an inference:
- observation:
something you experience with your senses (e.g., The shadow was short
in the fall, long in the winter, and short in the spring.)
- inference: something
you conclude based on observation (e.g., The shadow length will change
again by summer.)
- Students infer
whether the amount of daylight will increase or decrease between now and
summer. If students have difficulty inferring that there will be more hours
of daylight in the summer, ask them how late they remember being able to
play outside last summer!
- Extrapolate
summer daylight hours by continuing the graph using a ruler. (See
example.)
- Calculate hours
of daylight for the summer.
- Discuss the
patterns (winter=weak sun / longer shadows / less daylight ;
summer=strong sun / shorter shadows / more daylight ).
- Reinforce/compare
the differences in daylight hours from summer to winter in Ohio using a
globe.
- Mark Ohio so it
is easy to locate.
- Explain to students
that they are viewing the Earth from the sun.
- Tilt the globe
so that students have a direct view of the Tropic of Cancer (first day
of summer).
- Place Ohio in
a nighttime position (out of student view).
- Spin the globe
slowly counterclockwise (approximately one time zone per second) and
rhythmically tap for each time zone of rotation.
- Students count
aloud the number of time zones when Ohio is visible to the sun/having
daylight hours (about 15).
- Repeat the above
steps again, but this time students (the sun) have a direct view of
the Tropic of Capricorn (first day of winter). Expect only about
9 hours!
- Optional: Have
students adjust the graph for Daylight Savings Time by moving summer sunrise/sunset
ahead one hour. (Use example as an overhead
transparency to model.)
Day 5:
What Can a Model of the Sun and Earth Tell Us about the Seasons? (45-60 min.)
Ready...
- Gather the
following materials:
- Set up
lamp, globe, and North Star label.
- Mark the locations
for spring, summer, fall, and winter with masking tape.
- Wait to set
out labels for each season--students will
do this during the Closure lesson.
- Tape a magnet
on Ohio.
This will identify our part of the world.
- Place the
roofing nail on the magnet. This will allow you to demonstrate rotation
without having to retape the nail each time you pass the axis bar.
Get Set...
- Introduce
the activity to your students. "In this activity we will..."
- use a model to
investigate what causes the seasons to change
- revisit our learning
from the flagpole inquiry
- review what causes
day and night
- learn the difference
between rotation and revolution
- learn what makes
the sun appear to "rise in the east and set in the west"
- learn what makes
our solar system mainly a counterclockwise solar system
- phew!!!
- Tell students
what behaviors you expect of them before, during, and after the lesson.
- scientific thinking
- respectful listening
- speaking with
appropriate voices
- participating
- Explain how
today's lesson is grouped:
- a whole class
interactive demonstration
- Gather students
in a circle around the globe. Turn off all lighting except for the "sun"
lamp.
- Introduce
the globe lamp model. Point out that all models have flaws. A flaw in this
model is that the Earth and sun are not to scale. Note: An example of a
model to scale would be a tennis ball Earth and a sun as big around as a
class of students holding hands in a circle. In this model, the sun would
need to be 3/4 mile or more away from the Earth!
- Introduce
the terms rotation and revolution. (See Background
Information.) Show rotation by spinning the globe counterclockwise on
its axis. Show revolution by walking counterclockwise around
the sun. Point out to students that you are keeping the North Pole of the
Earth facing the North Star at all times.
Go!!!
- Demonstrate
a counterclockwise circle on the floor. Instruct students to trace their
fingers in a counterclockwise circle as well.
- Show counterclockwise
rotation for two days in each season by rotating the globe at the four seasons
points in the room. Be sure that the North Pole points to the North Star
as you circle the sun (lamp). Do not tell students which season is which.
- Discuss the
phrase, "The sun rises in the east and sets in the west." Use the globe
to show what causes this perspective (counterclockwise rotation of the Earth).
Discuss what makes this phrase misleading: The sun doesn't rise or set--the
Earth rotates.
- Mental Math:
Calculate the number of days in each season: 365 days divided by
four seasons...round 365 to 360 (easier than rounding to 370)...36 divided
by 4 = 9 plus a zero...a little more than 90 days in each season.
- Show approximate
rotations for one season. Spin the globe quickly as you slowly walk (counterclockwise)
from one season point to the next. Count quickly up to 90
to represent the 90+ rotations in a season.
- Show the Earth-sun
relationship for this season (e.g., strongest rays on the equator, in the
northern hemisphere, in the southern hemisphere). Point out the distance
Ohio is from direct rays at each season.
- Repeat the
above two steps for the remaining seasons. Have three of the "number
4" students do this.
- Question: Which
season is which?
- Connect to
the flagpole inquiry. Place the roofing nail on the magnet over Ohio.
With a piece of scrap paper, have a "number 4" student
sketch a shadow length at each season. Discuss which season location had
the longest shadow (winter), shortest shadow (summer), same length shadows
(spring/fall).
- Connect to
the flashlight and flagpole image used in December and March. Point out
that the sun has not become higher or lower in the solar system--rather,
the Earth's tilt has caused the shadow difference.
- Point out
that the first days of spring and fall are called equinox, which
is related to the word equal.
- Brainstorm
ways that spring and fall are equal (equal hours of daylight, sun hits directly
on the equator).
Day 6:
PutItAllTogether (45 min.)
- Distribute
the four season labels to four students in
the room. Ask them to use the information learned to decide where each label
should be placed. Each student should explain his or her choice.
- Summarize the
Main Points
- One rotation =
one day. One revolution = one year.
- Shadows are longer
in the winter and shorter in the summer because of the Earth's tilt.
- The Earth rotates
counterclockwise on its axis. The Earth revolves counterclockwise
around the sun.
- The counterclockwise
rotation of the Earth is what causes the sun to appear to "rise"
in the east and "set" in the west.
- The Earth's tilt,
combined with the revolution of the Earth, causes seasonal changes. Pass
out and discuss the Earth/Sun: A Year of
Seasons image.
- Make Some Sense
Of It (See Thinksheet page 2.)
- Compliment
students for appropriate behaviors during the lesson.
- Distribute
a class set of the Student Pages (for family
reading or in lieu of a textbook).
- Evaluation
- Formative: anecdotal
notes of teams in progress, incidental questioning of students' rationale
for what they are doing (during activity), observation of teamwork, status
of the class (end of each unfinished activity day)
- Summative: Choose
one or more of the following:
Want
Something More???
- Check out Related
Resources.
- What makes smog such
a problem in the summer, but not at other times of the year? Research
the connection between strong summer sunlight and smog. Create a display
or computer presentation entitled "Ways to Reduce Smog." See
Related Resources.
- Should we end Daylight
Savings Time? Research Internet articles related to the history and
rationale behind Daylight Savings Time. Hold a class debate on the issue.
- Health: Research
Seasonal Light Depression Disorder.
- Music: Play songs
related to the solar system and/or changing seasons and discuss. Examples:
"One Light, One Sun" by Raffi; "Almost Time" by David Wilcox.
If you have six to eight compasses, have teams do this. Note: If a compass
is not available, you will need to find a way to permanently mark the
location of the shadow. 
Leave this as a
classroom center for a few days so that students can manipulate it.
Leave this as a
classroom center for a few days so that students can manipulate it.
).
This will identify our part of the world.