Mystery Class
Jim Gilbert

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Mystery Class

Tracking Changes in Photoperiod Around the Globe

Mystery Class Updates will be posted on Fridays:
Feb. 6, 13, 20, 27, Mar. 6, 13, 20, 27, Apr. 3, 10, 17, 24, May 1, 8

Mystery Class Update: February 13, 1998

Mrs. Berger's 5th Grade Class
From the bottom of our hearts, thanks go to Mrs. Berger's class for providing this early Valentine's Day gift containing this week's set of sunrise/sunset data from our Mystery sites around the world. Her class REALLY gets around!

Remember, this information was recorded on Monday, the same day you collected your sunrise/sunset data. Don't forget to get up every Monday at sunrise! (Or find your local sunrise/sunset data from your local newspaper.)

Here are this week's data:

Journey North Mystery Class

Sunrise/Sunset Data

Data For: Monday, February 9, 1998

Mystery Class



# 1



# 2



# 3

0:00 *

0:00 *

# 4



# 5



# 6



# 7



# 8



# 9



# 10



*Journey North Mystery Class #3 reported 00:00 for their times because, right now, "the sun always shines!"

How To Organize Your Class

1. Divide Your Class into Eleven Groups

Give each group responsibility for one of the ten Mystery Classes, and give one additional group responsibility for your own site. Every week, each group can record the data and calculate the photoperiod for their site. Then, each group can share their calculations with the rest of the class. Each individual student can add the information to his or her own graph.

2. Give Each Group:

  • One copy of the Mystery Class Datasheet, to record sunrise/sunset times for each site(also found at page 98 of the Teacherís Manual.)

3. Make Your Own Mystery Class Graph

VERY IMPORTANT: In order for your graph to have enough room for a clear picture of the data, we strongly recommend that your graph be tall enough to prevent overcrowding!

Try This!

For a large classroom wall graph, we recommend the example of Wisconsin Third Grade teacher and Mystery Class expert Cathie Plaehn:

Her class creates a huge 3 x 3 wall graph using butcher-block paper to plot the mystery! Each student-group makes their own individual graphs, and the entire class plots data on the wall graph.

  • If you have a Teacherís Manual, follow the instructions on pages 99-100.
  • To make your own graph, use two pieces of 8 1/2 x 11 graph paper to allow at least an inch per day-length hour. Then, follow these instructions for assembling your graph:

A. Vertical Axis
Tape 2 graphs together, so the resulting graph is 22" tall. The left edge of your graph (the 11" side, which is the vertical axis) will indicate day length hours. Allow space for 20 day-length hours in total. At the lower left, begin with 4 hours of day length. Go up the vertical axis to 24 hours, and allow 4 squares for each hour.

B. Horizontal Axis
The bottom of your graph (the 8 1/2 inch side, which is the horizontal axis), will denote the dates of your Monday readings. Mark 11 weeks along the bottom, allowing three squares per week. Write the following dates for your Monday readings along the bottom of the graph:

Feb. 9, 16, 23

Mar. 2, 9, 16, 23, 30

Apr. 6, 13, 20

C. Example of a Mystery Class Graph: For guidance you can look at a smaller one page example, or for a graph that can be used by each individual student, look at the Mystery Class Graph

The Next Mystery Class Update Will be Posted: February 20, 1998

Copyright 1998 Journey North. All Rights Reserved.