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Background Is this spring the warmest in recorded history? Or is it the coolest? We often hear weather announcers discuss these things. How could you compare spring's arrival from year to year? What could you measure? In northern regions of North America, the melting of ice cover on lakes, rivers, ponds and oceans is a welcome sign of spring. This event is known as "ice-out", and ice-out dates are an accurate way to measure spring's pace from year to year. To begin, students will adopt a local body of water. If it's NOT frozen they'll report immediately, when the study begins in February. Using this information we can construct a mid-winter map to show the extent of winter's icy grip. As spring advances across the continent each site will report back when the ice has finally melted. Official 1998 Ice-out Sites Strategically placed across the Northern Hemisphere, these 6 official sites will monitor the ice-cover in their local waters. You'll be challenged to guess when the ice will melt at each of these places. Ice Location Lat/Long Chukchi Sea Point Hope, Alaska 68.5 N, 66.80 W Neana River Nenana, Alaska 64.5 N, 49.0 W Hudson Bay Rankin Inlet, NT 62.60 N, 93.50 W Lake Minnetonka Minneapolis, Minnesota 44.95 N, 93.54 W Walden Pond Concord, Massachusetts 42.25 N, 71.25 W River Teno Utsjoki,Finland(Lapland) 69.883 N, 27.017 E We'll also hold the fourth annual Internet Ice-Out Contest for Walden Pond. Students will be challenged to predict ice-out at Thoreau's famous pond by comparing records he kept in the mid-1800's against this spring's temperature records. How would spring be different if water never froze? Why does this fact affect all living things? Through a full range of activities, students will explore the connections between water, ice, temperature, and springtime. In addition to the "Spring Fever" lesson on page 113, on-line classroom experiments will be woven into this study.