CECsci.154


TITLE:    Discovering the Earth's Journey Around the Sun

AUTHOR:   Mark Whitener, IXL Elementary
          Arkansas City, Kansas

GRADE LEVEL:   5

OVERVIEW:  The revolution of the earth around the sun is a
phenomenon that is hard for students to deal with
concretely.  The following lesson will help students to more
fully understand our planet's relationship to the sun.

OBJECTIVE(s):  Students will observe the following about
shadows:
1.   The length of a shadow changes from week to week.
2.   The angle of the suns rays to the earth changes from
     week to week.

ACTIVITIES AND PROCEDURES:
     On the school grounds find a shadow cast by a fence
post or a piece of playground equipment.  Have students
observe the length and position of the shadow.  Students may
then make predictions about any changes that occur in the
length and direction of the shadow throughout the day.
Allow students to observe the shadow throughout the day.
     Students should then make predictions about the
shadow's length and angle of the ray to the earth if it is
measured at the same time every day.  Students should then
measure the shadow each day and graph the results.  (12:00
noon is an ideal time)
     At the end of each week find the average length of the
shadow and angle of the suns rays to the earth.  Students
will see a change in the shadow's length and the angle of
the sun's rays.

TYING IT ALL TOGETHER:
     Students should conclude from their data that the
position of the earth to the sun changes with the seasons.
Hence in spring the shadow will show that the angle between
the rays and earth has grown bigger and the sun is more
directly overhead thus producing warmer temperatures.