Journey North Mystery Class Spring 2005

Mystery Class Update: February 11, 2005

Today's Report Includes:

Another Set of Data worth Celebrating
Day Length Changes: What Do They Tell You?
More Tips from the Pros
Reasons for Seasons: Exploring the Astronomy of Spring
Who Knows What Time It Is? Responses to CQ #1
This Week's Sunrise/Sunset Times
Important: Plan Ahead and Mark your Calendars

Another Set of Data worth Celebrating
Your secret Mystery Friends have sent you an early Valentine's Day gift--their second set of sunrise/sunset data (recorded on Monday, February 7, 2005). With the winter season moving toward spring (or summer toward fall depending on your location), you'll see that sunrise/sunset "times are a changin" too. But do you know what the real "reasons for seasons" are? Find out in a new mini-unit of lessons below--read on!

Day Length Changes: What Do They Tell You?
As you plot this week's sunrise/sunset data on your graph, ask yourself the following questions. Can you determine:

1) Where is photoperiod changing the most quickly?

2) In which places is it increasing?

3) In which places is it decreasing?

4) What might these things tell you about the location of each site?

More Tips from the Pros
If you haven't already read her enlightening insights, Nebraska teacher and Journey North veteran Gayle Kloewer has some suggestions in this Teacher Tip to help students learn the most from the information on the graphs:

Teacher Tip: Mystery Class/Graphing Photoperiod

Reasons for Seasons: Exploring the Astronomy of Spring
As you begin to notice changes in your graph, begin to explore some of the reasons we have seasons. All seasonal changes - temperature, plant growth and life cycles, animal migrations, and so on - are due to the tilt of the Earth on its axis as it revolves around the sun. The tilt causes shifts in the amount of available sunlight (photoperiod) and its intensity (the angle at which it strikes the Earth). This series of lessons provides a backdrop for Journey North spring studies and can help you dispel some common misconceptions. Select those most appropriate to your curriculum focus and student readiness.

Reasons for Seasons
A Mini-Unit

Who Knows What Time It Is? Responses to CQ #1
Last week we asked about the meaning of two expressions that most people use everyday, but probably never stop to think about: "What do the initials 'A.M.' and 'P.M.' stand for anyway?" We also asked why these two abbreviations were created?

We had many correct answers from students across North America. Several answers took us for a quick Latin lesson on the meaning of these expressions and also explained WHY these abbreviations were created:

Roosevelt from Ms. Colucci's class explained:
"A.M. are the initials of the Latin phrase ante meridiem, which means before midday'. P.M. are the initials of the Latin phrase post meridiem,which means, 'post midday.' P.M. is used to indicate time between noon and 11:59 in the evening. I think that the abbreviations were created for the countries that tell time on a 12 hour clock. The time designations indicate which hours are morning and which are afternoon."

Tito, Ian, and Arthur from Mrs. Stafford's 5th Grade Class at M. I.
Day Elementary in Minerva, OH answered that: "A.M. means before noon and P.M. means after noon. They were created because A.M. is the abbreviation for ante meridiem and P.M.'s the abbreviation for post meridiem. We think they were created so people know if a time (like 3:00) is before noon or not."

And Mrs. Brohammer's 3rd Grade Discovery Class (Jamaal T., Alexander B., Jessica C., Emani J.) from Hambrick Elementary School in Stone Mountain, GA shared a similar conclusion: "A.M. stands for Ante Meridiem. P.M. stands for Post Meridiem. The words are from Latin and mean before noon and after noon. They have been in use since the 17th century (400 years). It has to do with the time of day before and after the sun crosses the celestial meridian - noon."

Our thanks and congratulations to all the students who answered Challenge Question #1. Nice job everyone! We wish we had space here to list all your answers.

This Week's Sunrise/Sunset Times
Remember, the secret Mystery sites recorded their times last Monday, the same day you collected your own local sunrise/sunset data.

Link to This Week's Sunrise/Sunset Data

Important: Plan Ahead and Mark your Calendars
Here's the 2005 Mystery Class Schedule so you know what to expect from Journey North. Please be sure to plan ahead.

February 4- April 15:	Each Friday, Sunrise/Sunset Times are posted for the ten Mystery Sites.
March 11:	The "Longitude Clue" is posted.
March 18, 25, April 1, 8 & 15:	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 22: Deadline for Your Answers!	No late entries will be accepted (out of fairness to all participants, no exceptions.)
April 29:	Mystery Sites Revealed!
May 6:	Meet Your Mystery Friends!

Questions? See Mystery Class FAQ's

The Next Mystery Class Update Will Be Posted on February 18, 2005