Download Sun Shadow

Procedure for Sun Shadow Activity:
1.
WARNING! Never look directly at the soon as this can cause permanent
damage to your eyes.
2.
For this activity you will be working in pairs to observe the changes to shadows
that occur on a daily, weekly, and monthly time scale. You will take observations
of shadows over a three month period, recording data three times per week. On
days that you observe, you will take three measurements per day, e.g. at 10am,
noon, and 3pm. You can choose which times you take data but they must be
spaced out throughout the day.
3.
Once you pick which times to take data, you must use the same times to
measure the shadows each day to ensure consistent data. Also you must pick a
location where you will measure shadows, make sure that this location is not
obscured by trees or buildings at the times you choose to observe. To recap,
every observation must be taken at the same location, and every day you must
take data at the same times.
4.
Before you begin, record in your notebook what you believe the evolution of
shadows will look like over the course of one day, of one week, and one month.
We will see if your observations meet your expectations.
5.
When you make your observation, you will have to choose which person will
create the shadow and which person will measure, unless you and your partner
are exactly the same height you will have to stay in your roles throughout the
activity. On your first observation record the height of the person making the
shadow, the location you pick, and the times you will observe. These will not
change so record this data once in your notebook.
6.
Record your data in a table like Data Table 1, the data, time, and shadow length
should be written down for every observation.
DATA TABLE 1
Date
Time
Shadow Length
December 27, 2011
10:35 am
60.7 cm
Supplies:
One partner (work in groups of two)
Two meters of paper ruler
Notebook to record data
Time:
Multiple observation of the course of three months
Question and Conclusions:
1.
Look back at your initial thoughts, is it different from what you pictured in your
mind in step 4. If so, how?
2.
What conclusions can you make about how shadows change over the course of
one day, one week, one month, and three months.
Important Vocabulary to Know:
Sun:
The star that is the central body of the solar system, around
which the planets revolve and from which they receive light and
heat: its mean distance from the earth is about 93 million miles
(150 million km), its diameter about 864,000 miles (1.4 million km),
and its mass about 330,000 times that of the earth; its period of
surface rotation is about 26 days at its equator but longer at higher
latitudes.
Shadow:
A dark area or shape produced by a body coming between rays of
light and a surface.
Angle:
The space (measured in degrees or radians) between two
intersecting lines or surfaces at or close to the point where they
meet.
Horizon:
The apparent line that separates earth from sky, the line that
divides all visible directions into two categories: those that intersect
the Earth's surface, and those that does not.
More Online Resources:
Shadow:
http://en.wikipedia.org/wiki/Shadow
Shadow:
http://www.nasa.gov/audience/forstudents/k-4/stories/F_Keeping_Cool_With_Shadows.html