Meter stick

Magnetic compass

Lab books

Heavy washer

50 cm of string

Chalk

Student Worksheet (Spanish)

Data table (Spanish)

1. Select other schools, preferably far removed in terms of latitude, with which your class will cooperate in this investigation.

2. Find a level, sunny location on the school yard, preferably with concrete or asphalt. Choose a convenient time of day to make measures of shadow length. It should be a time which is available daily over an extended period of time. Look at your local weather patterns related to the likelihood of morning fog and other conditions which can block the sun. It may be more interesting to have different groups of students measure shadow length at different times of the day, so that the observations can be compared and analyzed.

3. Structure your students into groups of at least two people each. One student will need to hold the meter stick in a vertical position while the other student measures (or marks with chalk) the shadow's length.

4. Teach each group procedures for holding the meter stick in a vertical position. The vertical position can be found using a "plumb bob." Tie a heavy washer onto a string. Tie the string onto the student's index finger so that it can hang along the meter stick as the student holds the rule in the vertical position. Hold the meter stick so that the string runs along the meter stick.

5. Teach the students how to accurately read (and record) measures taken off a meter stick. Also teach the students how to read a magnetic compass angle and how to use the meter stick to extend the angle between points.

6. Take the groups to a location on campus where the ground is level (horizontal). Using the "plumb bob" on the meter stick, the students should position the meter stick in the vertical position, and measure the length of the shadow. Measure the magnetic compass angle along the shadow toward the sun. Students should carefully record the following information (see student data table in English, and in Spanish):
   1. Teacher's Name
   2. School
   3. City
   4. State, latitude in degrees and minutes
   5. Time of day when shadows were measured
   6. Dates
   7. Lengths of Shadow (to nearest centimeter)
   8. The Magnetic Compass Angle to the Sun

7. Repeat step 6, taking care to make the measures at the SAME TIME of day, over a period of several weeks. If possible do the investigation near the equinox (March 21 or September 23), when the sun's position in the sky is most rapidly changing.

8. Prepare a chart containing information relating "date" to "length of shadow." The time of day and the length of the meter stick making the shadow are kept constant in the investigation.

9. Telecompute the information contained in your chart to the other schools with whom you are working on this investigation. Telecompute the information on the student data table: names, period, school, city, latitude, state, date, time, shadow in cm, compass angle.