This post was edited by jayanthi rangan on Mar, 2007
This term my classes are participating in a program called ‘mystery class’ which is one of the “Journey North” program. The website address is: http://www.learner.org/jnorth/tm/mclass . I enthusiastically endorse this program to use with ‘excel’ to enhance Earth Science curriculum (Seasons) and associated social studies curriculum.

This program starts at the end of January and goes on till May. Every week the participating classes get a data sheet with the times of sunset and sunrise for ten different locations in the world. Based solely on the photoperiod of these sites on a particular date, the participating classes are supposed to find out the ten mystery locations. The element of mystery, the anticipation of new clues, the science behind the sunrise/sunset numbers, and the data manipulation, add to the success of this program and involve children thoroughly.

In my school 6-8 grades are involved in calculating the photoperiods of each location and charting them on excel on a regular basis. However, upper elementary children can use this program effectively too. There are other resources listed (books and websites) which come in handy too.

The questions I have asked children lead them into making connections with seasons. The following assessment chart from Journey North further streamlines the subject area.

The orientation of the Earth and Sun throughout the year.
How the tilt of the Earth combined with its revolution around the sun affects daylength (photoperiod) and the angle (intensity) of sunlight at in different seasons.
How differences in photoperiod and angle of sunlight affect seasonal temperatures.
How daylength varies with latitude during different seasons.
The characteristics of the solstices and equinoxes in terms of the Earth/Sun orientation, daylength, and angle of the Sun in relation to Earth.
How and why shadows change over the course of the year.

The questions include:

1. What patterns do you see in the data from week to week?
2. Are the photoperiods increasing or decreasing? Is there any photoperiod that has not changed at all? Where might this location be?
3. Is this photoperiod increase/decrease minimum or dramatic?
4. Does the dramatic change in photoperiod, give us any clue about its location?
5. Based on what we know already, what does the increase/decrease in photoperiod tell us about the season?

I enthusiastically encourage teachers of Earth Science, Geography & Social Studies to try out the web site for teaching change of seasons, photoperiod change, Longitudes and Latitudes etc.

We charted our weekly charts on Excel even though we could not fully use excel's calculations which are based on the decimal system. Subtracting hours and minutes was different indeed. The excel worksheet is attached. The previous one does not open properly.

Jayanthi, this activity sounds really cool. I'm going to put this on 'my list' for next year!

Becky

The latest Excel file is attached.

I am posting the social and cultural clues posted on the site. These clues are to be viewed along with the longitudinal clues to figure out the mystery locations.