Journey North Mystery Class Spring 2006

Mystery Class Update: February 17, 2006

Today's Report Includes:

Most Recent Sunrise/Sunset Data
Is Something More than Day Length Changing?
If You Could Un-tilt the Earth: Challenge Question #1
Important Prep. for Upcoming Longitude Clues: Understanding GMT
Word Up! Mystery Class Glossary
What's Next? Check the Calendar

Most Recent Sunrise/Sunset Data
The third set of Sunrise/Sunset data has now arrived:

This Week's Sunrise/Sunset Data
Need to Catch Up?
All Sunrise/Sunset Data to Date

Is Something More than Day Length Changing?
As you plot the changing day length data on your graphs, keep in mind that sunlight affects all living systems. The sun is at the base of the food chain. Sunlight makes plants grow, animals eat these plants, predators prey on these animals, and so forth.

As day length changes at the Mystery Classes around the planet, stop to think about how the food chain is changing too. For example, during spring in the Northern Hemisphere, sunlight and photosynthesis increase, temperatures rise, and food production increases. The animal movements you track and the signs of spring you witness will be related to daylight in one way or another.

Explore the Connection:

First, watch Journey North's founder and Director, Elizabeth Howard, summarize the Sun's central connection to all life
	*The Sun's Connection* Video Clip (Tips)

Then, come back and try this "enlightening" activity:

Students create webs, and grasp the central role of sunlight in living systems:

Seeing the Light

If You Could Un-tilt the Earth
Last week you discovered that the Earth's axis isn't oriented straight up and down, but instead is tilted 23.5 degrees in relation to the sun.

Click on image to enlarge

Challenge Question #1:
"What do you think your climate and seasons would be like if the Earth were not tilted on its axis? Why do you think so?"

To respond to this question, please follow these instructions.

Important Preparation for Upcoming Longitude Clues: Understanding GMT
The weekly sunrise/sunset time data that you have been graphing will help you estimate the ten secret sites' relative LATITUDE. But you'll also need to know the sites' approximate LONGITUDE in order to narrow your search. When it comes to estimating a site's LONGITUDE, however, the sunrise/sunset time data doesn't give you all the tools you need.

In just a few weeks, on March 10, we'll provide a different kind of time data called GMT or UT time (for Greenwich Mean Time or Universal Time) to help you estimate the secret sites' Longitude.

To prepare, let's start this week by looking at important background information about GMT. Next week we'll look at Latitude and Longitude in more detail.

The GMT lessons below will help you understand two important central concepts for the Longitude Clues:

(1) GMT or Universal time keeping:

What is GMT Time Keeping?

You make the call!

(2) And that "sunrise" and "sunset" don't result from sun movement. Instead, Earth spins one complete rotation (360 degrees) on its axis every 24 hours, which brings an area of Earth into the light of the sun in the morning and then out of it in the evening.

Does the Sun Really Rise and Set?

Mystery Class Glossary
Don't miss this chance to build your vocabulary with terms used in our reports. Find the following terms from this week's report and define them in your journals or portfolios before going to the Glossary: GMT, Prime Meridian, Longitude, Earth's Axis and Earth's Rotation.

Bookmark the Mystery Class Glossary

What's Next? Check the Calendar

February 3- April 14:	Each Friday, Sunrise/Sunset Times are posted for the ten Mystery Sites.
Feb 17, 24, Mar.3:	Getting Ready for the Longitude Clues
March 10:	The "Longitude Clue" is posted.
March 17, 24 & 31, April 7 & 14	Interdisciplinary clues from the Mystery Sites are posted each week. (Please Note--out of fairness to all participants, we will only post the clues on their scheduled dates.)
April 21: Deadline for Your Answers!	No late entries will be accepted (out of fairness to all participants, no exceptions.)
April 28:	Mystery Sites Revealed!
May 5:	Meet Your Mystery Friends!

Have Questions? See Mystery Class FAQ

The Next Mystery Class Update Will Be Posted on February 24, 2006