Notes
on the Investigation
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Click
for Student Datasheet |
Preparation
Involve students in choosing an area in the schoolyard or
playground that gets a lot of sunlight. Options:
Instead of measuring a stick's shadow, students can also use
a flag pole, fence post, or other vertical object with a clear
area to the north.
Data Sheets: Students use these to document
hourly measurements and observations. They can make their
own or use this printable version.
Optional Indoor Setup
Consider setting up a mock flagpole in the classroom, by sticking
a pencil in a spool, for instance. Shine a flashlight at it
from directly above and then move the light down so it hits
the “pole” at an angle. Ask, What happens
to the shadow? What do you think causes it to get longer and
shorter?
Making
Connections — Discussion and Journal Questions
What patterns did you notice?
How would you explain them?
What general statement(s) could you make about shadows and
sunlight?
What questions do you still have?
What
to Expect: Findings
Students should find that shadows always point north of the
sun. (In this hemisphere, the sun always appears to the south.)
They may also discover that shadows seem to move clockwise
in a semi-circle and that they are shortest at noon when the
sun appears “highest” in the sky. Shadows are
longest in the early morning and late afternoon/early evening
when the sun appears low in the sky. As the Earth rotates
on its axis, the sun hits each location in the morning at
an angle. This becomes more vertical as the sun appears to
pass more directly overhead around noon. (It’s actually
the Earth that is “passing” as it rotates!) As
Earth continues to spin toward sunset, the increasing angle
causes shadows to lengthen!
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