Today's Update Includes:

• Countdown to Mystery Class: Two Months to Go!
• Teacher's Practice Packet #1: Discovering Latitude Clues
• Teacher's Practice Packet #2 (coming January): Longitude Clues
• Preparing Students for Mystery Class: Time, Seasons and the Globe

Reminder: Your goal this fall is simply to invite students to think about the relationships between sunlight and Earth's daily and seasonal cycles. Build interest as you and your students make observations, collect data, ask questions, and explore various activities such as those in these Countdown to Mystery Class postings.

The weekly sunrise/sunset data your students receive during Mystery Class will slowly reveal information about the latitude of the 10 Mystery site locations.

Teacher Practice Packet #1 includes the actual, start-to-finish sunrise/sunset data from last year's Mystery Class season. This practice packet will help you discover for yourself the relationships between latitude, sunlight, and seasonal change when you:

• Practice calculating photoperiod.
• Plot the data on a graph.
• Examine the data to find patterns and surprises.
• Make predictions and compare findings.
• Reflect in your Mystery Class journal.

We hope the practice packet will give you a chance to experience the process of discovery your students will have when they begin to collect, organize, and analyze data to identify the locations of this year’s mystery classes.

• Teacher's Practice Packet #1: Discovering Latitude Clues

Each spring during Mystery Class, we reveal special longitude clues at the time of the spring Equinox. Leading up to the Equinox, students will have discovered clues about the latitude of the Mystery sites through sunrise/sunset data, but nothing about the longitude.

• Watch for Practice Packet #2 in early January for a chance to practice using longitude clues to find the Mystery site locations.

Place students in small groups with a globe, index cards, and pencils. Invite them to think about the globe in a new way by posing a challenge:

"Solving mysteries takes special skills. You have to be able to examine something closely and ask lots of questions. The globe is a model of Earth. Each part of this model of our planet is designed to give us information about the world. How is a globe like our planet Earth?"

Give each group five minutes to study how the globe is constructed and zoom in on each of its parts. After students have had time to explore, present their task:

• Which parts of the globe can be used to explain the Earth's daily and seasonal cycles?

As they explore the globe searching for clues about how it can be used to learn about time and seasons on Earth, tell them you will be walking around and listening for "sleuth-speak," where they're asking lots of questions about everything they see. (Why is Earth shown tilted on the globe? Why does it spin? Is the Earth a perfect sphere? How long does it take for the Earth to spin once around the axis?, etc.)

As students study the shapes, colors, lines, words, numbers, and parts of a globe that might reveal information about seasons and time, be sure to have them think about what the globe might reveal about the Earth's position and movement in space, as well. As they make discoveries invite students to think: What is this and why?

Have students record 3-5 of their most intriguing questions on an index card. Collect and seal their questions in an envelope to be opened and revisited at the end of Mystery Class to showcase what they've learned.

What can a globe tell us about time and seasons on Earth?