Follow
the Sun for a Day
Creating an Earth/Sun Model
Time
1 period, then a few minutes each hour through the day
Materials
clear 2-quart bowl, large sheet of white paper taped to a piece
of cardboard or other rigid item, sharp pencil, erasable marker,
compass, crayons or colored pencils |
Teacher
Background |
Standards
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Overview
Students create a simple model of the Earth and sun as seen from space.
They use it to explore the sun's apparent movement across the sky over
the course of a day. They begin to understand that the sun appears to
move west, but that it is the Earth's rotation toward the east that causes
this phenomenon. This lays the groundwork for understanding Mystery Class
longitude clues.
Preparation
Conduct this activity on a sunny day.
Laying
the Groundwork
Invite students
to imagine they are far out in space and can see the Earth and our sun.
Ask, What would you expect to see happening and why? Make four different
drawings, to show what you'd see during a day. Once students have
completed this, ask, What questions do you have? Save these
for students to revisit during and after this activity.
Exploration
- Make
an X in the center of the paper to represent our Earth.
- Take
the materials outside. Find a level surface for the paper. Make sure
the location receives sunlight all day.
- Place
the bowl upside down on the paper. Ask students to imagine it's our
atmosphere. Mark an x on the center of the bottom of the bowl with
the overhead marker. Make sure the x on the paper is lined up under
the x on the bowl. Trace the edge of the bowl onto the paper to make
it easier to line up.
- Have
students use a compass to determine North for your location. Once
they've reached consensus, they should mark North on the paper and
the bowl.
- Each
hour, have a student touch the side of the clear bowl with the tip
of the pencil so the shadow of the pencil's tip falls on the X on
the paper. Have a partner make a dot on that spot with the marker.
(Putting a number beside each dot will help students recall the order
in which they made observations.) After each dot goes on, ask, Where
do you predict the next dot will be? Explain your thinking. Which
direction does the sun appear to be moving?
Note: To get accurate results, the bowl must sit in the same
location and be lined up in the same way for each hourly reading.
Making
Connections —
Discussion and journaling questions:
- What
patterns did you notice over the course of the day?
- How
would you explain them?
- What
general statement(s) could you make about the daily movements of the
sun and Earth?
- What
questions do you still have?
What
to Expect
The Earth rotates counterclockwise, toward the east. However, the sun appears
to be moving west over the course of a day. Students' earlier explorations should
have revealed that the sun does not move. Rather, it is
the Earth's rotation that makes the sun appear to move west.
The Living Earth® image is a composite of Earth satellite
imagery developed by The Living Earth, Inc. From: The
Earth and Moon Viewer
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Assessment
Once students
have completed the exploration, ask them to revise the drawings they
made during Laying the Groundwork. They can either create new ones or
use another color to make changes. Their responses to the discussion
and journaling questions along with the changes in their drawings should
reveal an enhanced understanding of the daily Sun-Earth relationship.
Also see these assessment tasks:
Criteria: Student can explain via words, models, drawings, or actions: |
Beginning |
Developing |
Mastery |
The
orientation of the Earth and Sun throughout the year. |
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How
the tilt of the Earth combined with its revolution around the
sun affects day length (photoperiod) and the angle (intensity)
of sunlight at in different seasons. |
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How
differences in photoperiod and angle of sunlight affect seasonal
temperatures. |
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How
day length varies with latitude during different seasons. |
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The
characteristics of the solstices and equinoxes in terms of the
Earth/Sun orientation, daylength, and angle of the Sun in relation
to Earth. |
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How
and why shadows change over the course of the year. |
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