Mystery
Class Update: February 17, 2006
Most Recent Sunrise/Sunset Data The third set of Sunrise/Sunset data has now arrived:
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:
Then, come back and try this "enlightening" activity: 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.
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:
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.
What's Next? Check the Calendar
The Next Mystery Class Update Will Be Posted on February 24, 2006
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