News Flash: Ice-out at Thoreau's Walden Pond "And the winners are....." "It has happened. . .the ice at Walden is OUT!" announced Michelle Dumas of Walden State Park Reserve. The official date for Ice-out was April 12, 2001--sometime during wee hours when park officials were home in bed. Fifteen days ago, Michelle wrote this: "The pond is 99.9 percent ice-covered. My ice-out guess date was today (3/28), so it looks like I lost!" Today Michelle told us that the pond was about 50 percent ice-covered when she left yesterday, and a lot of rain helped speed the ice-out during the night. Two Close Calls! Michelle missed the date, but Journey North students came closer. Congratulations to two East-coast classrooms for their nearly precise Pond Predictions! Mrs. Nunnally's Second Grade Class at Peter Woodbury School in Bedford, NH came the closest with their guess. "We think the ice will go out on Walden Pond on April 14. We noticed that the ice is going out later now than it did in Henry Thoreau's time. Also we know there is a lot of snow in New England right now so we don't think it will happen in March." (NUNNALLYR@sau25.net) Iselin (New Jersey) Middle School 7th Graders Ryan, Nihar, Nicole, Aisha, and Sean were next. They said, "We think that ice out will occur on Walden Pond on April 16, 2001. (iselin5@injersey.infi.net) How did they figure? Compare Thoreau's ice-out records from the 1800s to those for the late 1900s and 2000, collected by Journey North students. Then tell us what you think! Challenge Question #20: "According to Thoreau's records, what was the average ice-out date during his time? What is the average date during our time, according to records kept by Journey North students? How might you explain the change?" (To respond to this question, please follow the instructions below.) Ice-Out Records for Walden Pond Collected in the 1800s by Henry David Thoreau: 1845 April 1 1846 March 25 1847 April 8 1851 March 28 1853 March 23 1854 April 7 .....and in the 1900s/2000s by Journey North students: 1995 March 18 1996 March 23 1997 February 22 1998 February 26 1999 March 1 2000 March 9 Introducing the Next Official Ice-Out Observation Post Lake Minnetonka Next in line to thaw should be Lake Minnetonka. This still-frozen lake is located right outside the window of the Journey North headquarters in Minnesota. People here have always been eager for spring, and for the past 114 years they've kept ice-out records for this lake. By law, all ice-fishing houses must be off the ice by March 1st, because cars & trucks must DRIVE on the ice in order to remove the houses. Ice-out dates are one of the best natural ways to measure the amount of heat the earth has received, and to compare spring's pace from year to year.Year 2000 ice-out on Lake Minnetonka was the earliest in decades, but Minnesota's 2001 winter has been colder than the past few years. (Remember: We define "ice-out" as the time the body of water is 90% free of ice.) Look at the chart showing 114 years of records: Link to 114 years of Ice-Out Records for Lake Minnetonka Then give us your final answer to this question: Challenge Question #21: "When do you predict ice-out will occur on Lake Minnetonka in Spring 2001?" (To respond to this question, please follow the instructions below.) How to Respond to Today's Challenge Questions Please answer ONLY ONE question in each e-mail message! 1. Address an e-mail message to: jn-challenge-spring@learner.org 2. IMPORTANT: In the Subject Line of your message write: Challenge Question #20 (or #21). 3. In the body of the message, give your answer to one of today's questions. Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form