Creating the Earth-Sun System in the Classroom
Students explore a model of the earth’s daily rotation and its
annual revolution around the sun. They try to figure out at which point
each season occurs in their part of the world. This lays the groundwork
for understanding the reasons for seasons and for making sense of Mystery
Prepare a simulation of the Earth-Sun system by placing a lamp on the
floor to represent the sun. Use a globe to represent the earth. It will
spin (rotate) on its axis and revolve around the sun. Cut a star shape
out of paper, label it the North Star, and place it on the board. Orient
the North Pole of the globe so it points toward the star. Finally, place
4 Xs of masking tape on the floor on each side of the lamp.
Ask a student
to find your city or state on the globe and tape a small paper circle
on it. Challenge them to keep an eye on this location – and the
light it receives – as they explore how the Earth and sun interact!
the terms rotation and revolution.
Have a volunteer demonstrate rotation with his or her body and then
with the globe. (You might reveal that spinning is another
word for rotation.) Next, let them know that the Earth rotates counterclockwise
on its axis. Have a volunteer demonstrate this. Ask students to notice
what happens to the light hitting your globe's school location. Ask,
What do you think each rotation represents? Explain your thinking.
(Each represents a 24-hour day during which every location has daylight
another volunteer to show how the Earth moves (revolves) around the
sun (also counterclockwise). Explain that the Xs represent different
seasons and that the Earth is not up and down on its axis, but always
tilted (23.5 degrees) with the North Pole facing the North Star at
all times. As the student walks around the sun slowly to represent
the earth’s revolution, remind him or her to spin the globe
quickly to also represent days passing. Ask, What do you think
one complete revolution represents? (A year or 365 ¼ days.)
a volunteer to stand at one of the Xs and rotate the earth to show
two days coming and going. Have another student take the globe and
move counterclockwise to the next X and do the same, and so on with
each season. Remind them to keep the North Pole pointing to the North
Star as they revolve around the sun from season to season. As they
do so, ask students to pay close attention to the sun's relationship
to their hometown during each season.
small groups to discuss which X they think is which season. You might
prompt them to focus on their hometown and discuss characteristics
of each season there: temperature, sunlight, and so on. They may want
to again examine the relationship between their hometown circle and
the lamplight on the globe. Also share this clue with them: the first
days of spring and fall are called the equinox, which is
related to the word equal.
each group write a label for each of the four seasons and place the
labels face down on what they think is the appropriate X. Then season
by season, turn over the labels and ask each group to explain its
thinking. Conflicts in labels should spark fertile discussions! Rather
than confirm answers at this point, you might want to conduct the
next couple of activities and revisit students’ ideas at the
end. Alternatively, you can pass out and discuss the Earth,
Sun, and Seasons drawing.
Students: Have students draw diagrams showing the relationship
between the earth and the sun as it would be on the day they are doing
this activity. Then have them sketch North and South America on their
"earth" and place a small x in the approximate location of
Younger Students: Give students this challenge question:
One day, a boy in Massachusetts is going skiing with his family. What
might a girl in Australia be doing?
(Also see these assessment tasks.)
Set up a model of the earth's annual revolution around the sun in the
classroom and keep it active all school year. Put the sun in the center
and create an Earth with the proper tilt. Mark a pathway the Earth will
follow on its 360-degree revolution. Mark both equinoxes and solstices
along the path. Try to make the model large enough so each week's changes
are visible. Once each week, have students move the earth to its proper
position in relation to the sun.