Learning Cycle Planner by Joe Orzali
Tracking the Sun’s Path in the Sky Lesson
Common Curriculum Goal:
Topics: Earth and space science, natural cycles, alternative energy, green
building, and ecological preservation
Learning Objective: Students get outside and learn how to orient buildings to
utilize passive and active solar energy.
Exploration Phase:
Hands-on Activity: Tracking the Sun’s Path in the Sky
Exploration through Media: Video: Planet Earth Pole to Pole:
http://www.youtube.com/watch?v=heFCzUT8FaM
Focus on how the seasons are dramatically affected by the lack or abundance of
sunlight in Polar Regions.
Research: Solarize Portland (articles):
http://www.solarizeportland.org/index.html
http://www.mrsunsolar.com/solarize_sw.php
Concept Development Phase:
Concepts to be taught: Heat transfer, renewable and non-renewable energy,
residential energy use, resource consumption, pollution and waste, ecosystem dynamics,
energy flow
Procedures to be taught: Inquiry, experimental design, graphing, model making
Activities: Invite a guest speaker from a local solar installation company; request
that they present information about the solar energy market and jobs installing solar hot
water heaters and photovoltaic systems.
Field Trips/ Learning beyond the Classroom:
Visit Fire Station at SE 52nd Ave and Mall St. large PV array.
Visit Mr. Sun Solar (the largest solar installer in Portland, OR)
http://www.mrsunsolar.com/.
Volunteer for Portland’s Green Homes Tour 9/25/2010:
http://www.portlandonline.com/bps/index.cfm?c=41893
Teaching across the Curriculum: Geometry- calculating the angle of the sun
Tracking the Sun’s Path in the Sky
(Adapted from Jones, 1996 and altered by Orzali, 2010).
Materials: clear plastic dome (3" to 8" diameter or clear tops of "Leggs" pantyhose
containers will work); grease pens or water-soluble markers; adhesive colored dots; (as
an alternative to a plastic dome, a large kitchen strainer and sewing pins with large heads
can be used); 9" x 12" oaktag or other stiff paper; compass.
Procedure:
This activity allows us to track the apparent motion of the Sun in the sky on a model in
which the plastic dome represents the sky. To do this, we mark the position on a clear
dome which casts a shadow at the same central spot. As the Sun moves in the sky, so too
does the position we must mark. For this activity, an outside spot must be picked which
will not be shaded at any time during the day.
How does the Sun appear to move across the sky? How could shadows tell us about the
Sun's position?
1. Begin early on a sunny day. Place a clear plastic dome or a large kitchen strainer
on a sheet of oaktag and trace the outline of the dome on the oaktag. Draw a mark on
the edge of the dome and on the oaktag, so the alignment of the dome and oaktag can
be checked before each observation. Remove the dome and mark the center of the
circle just traced. (The center can be found by drawing two intersecting lines across
the widest part of the circle.
2. The dome represents the sky, the center mark represents your position on the
ground.
3. Having carefully selected an unshaded spot for the observations, place the oaktag
on level ground. Trace the outline of the oaktag on the ground with chalk, so that its
position can also be verified before each observation. Replace the dome on the oaktag
outline aligning the marks on the dome and the oaktag. Using the compass, mark a
North-South arrow and an East-West arrow on the corner of the oaktag.
Note: Use duct tape, or spray paint to mark the position of the oak tag on the ground
so that is remains for the duration of the project.
4. Mark the spot on the dome whose shadow falls on the central dot. If using a
strainer, large headed pins will work well. For a plastic dome, use an adhesive dot or
a grease marker. (It may be easier to use the end of a pen to locate the position before
marking it with an adhesive dot.) Number the marks and keep track of the times of
the observations in a notebook. Continue to make observations at regular intervals
throughout the day. At the end of the day, label the compass directions on the dome,
date it, and keep the dome for comparison with later observations.
Resources:
Source: http://www.nkba.org/images/prl_image_library/kb_systems/Page-17--Figure-3.2.jpg
Helpful Information:
Remind students: Be sure to remind students that looking at the Sun can cause permanent
eye damage. Never look directly at the Sun!
Analysis:
You should be able to convince yourself that the marks placed on the dome correspond to
the position of the Sun in the sky at the recorded times. If an observer (maybe an ant)
were to stand at the central dot inside the dome, then each time a dot was marked
eclipsing the Sun (casting a shadow on the observer), the dot would have to be in the
direction of the Sun. The position of the dot, then, would have to be the same as the Sun's
apparent position in the sky.
Discussion:
What sort of path does the Sun follow in the sky? Did the Sun travel directly over the top
of the dome? Where did the Sun begin in the morning? Where was it in the afternoon?
What about at noon? At midday?
Extension:
Challenge students predict the path of the Sun in a different season.
References:
Jones, C., Ruiz, T., Waters, S. & Breen, J. (1996). Eyes on the sky feet on the ground.
Retrieved July 29, 2009, from http://heawww.harvard.edu/ECT/the_book/Chap1/Chapter1.html
© Joe Orzali 2010