1. Glaciers October 21st, 2009

2. Pre - Activity Knowledge Check on the note sheet provided, answer the true or false questions

3. Glacial Power http://www.youtube.com/watch?v=cIBFAke90SI

4. Glaciation of Canada at one time, ice sheets covered much of North America the last ice age ended approximately 10, 000 years ago, at which time 30% of the land was covered and glaciers were up to 1000 km wide (about the distance from Montreal to Windsor) and 100m thick today only about 10% (mostly Antarctica) of the earth is covered by ice sheets

9. What is a glacier? a large mass of ice and snow that moves over the earth's landscapes generally formed by the continual accumulation (continuously building up) of snow that compacts into ice formed in areas where temperatures are so low that snowfall does not melt entirely during the summer today, such conditions are found only at high latitudes (North / South poles) or high altitudes (the Alps, Rockies, Himalayas)

10. Konkordia, Switzerland

11. Types of Glaciers Continental glaciers (high latitudes) cover large areas of land found in areas of high latitude (North / South poles) in their most extensive form are referred to as ice sheets example: Greenland

12. Alpine glaciers (high altitude) found in he mountainous regions (high altitudes) located in bowl-shaped hollows or valleys on the mountains continually grow from a collection of snow (snowfield) near the top

13. Movement glaciers are constantly advancing and retreating, despite the movement not always being visible to the naked eye glaciers shape land through scraping and depositing material (deposition) as the snow and ice buildup continues, glaciers move thicker continental glaciers move outward from the centers of accumulation (think of a mound of play-doh being squished down) smaller alpine glaciers aided by gravity, move downhill

14. Glacier Advance / Retreat Model http://www.uky.edu/AS/Geology/howell/goodies/elear ning/module13swf.swf

15. There are 3 main mechanisms by which glaciers are thought to move: Creep Basal Slip Shearing

16. Creep the pressure of the overlaying ice causes the crystals to be crushed and produced and an outward or downward movement under the influence of gravity creep occurs very gradually and seldom amounts to more than a few centimeters per day

17. Basal Slip occurs when there is a thin film (layer) of water between the ice and rock movement is more rapid than creep (up to 1 meter per day)

18. Shearing process is similar to faulting usually occurs when glaciers are moving down slope sometimes ice in glaciers cannot adjust to the pressures produced by creep and basal slip so the ice shears as it moves forward, producing deep cracks in the ice called crevasses

19. Shearing / Crevasse Model http://highered.mcgraw- hill.com/sites/0072402466/student_view0/chapter12/a nimations_andmovies.html#

21. True / False answer the same true / false questions on the note sheet from the beginning of the lesson

22. Glaciers and Climate Change www.youtube.com/watch?v=M3g1iZn95sc

23. Exit Card pull out a sheet of lined paper on that sheet of paper, WRITE DOWN AS MUCH AS YOU KNOW ABOUT GLACIERS you have 2 minutes

24. Homework use your textbook pages 118 - 125 for this work (you can also use an atlas) do questions 1, 2, 4, 5, 7 and 8