CALC Time Needed for a Lake to Freeze Over. (a) When the air temperature is below 0o C, the water at the surface of a lake freezes to form an ice sheet. Why doesn’t freezing occur throughout the entire volume of the lake? (b) Show that the thick-ness of the ice sheet formed on the surface of a lake is proportional to the square root of the time if the heat of fusion of the water freezing on the underside of the ice sheet is conducted through the sheet. (c) Assuming that the upper surface of the ice sheet is at – 10o C and the bottom surface is at 0o C, calculate the time it will take to form an ice sheet 25 cm thick. (d) If the lake in part (c) is uniformly 40 m deep, how long would it take to freeze all the water in the lake? Is this likely to occur?
Pacific NW is decreased snowpack will be negatively affect water resources most in Summer ● Less rainfall, relying on snow melt (less snow) ○ Falling as rain instead of snow Coastal Population: ● People will be impacted by increased sea levels ● 39% live in a coastal county ● Low lying island nations will be greatly affected (Maldives, Tuvalu, Bahamas, Caribbean nations) ○ These nations could disappear ○ Very vulnerable (lose all of their land potentially) Bangladesh: less than 5 meters above sea level, become vulnerable, flooding will occur Coastal Louisiana: very vulnerable below 1.5 meters below sea level ● Vulnerable to hurricanes ● Disappearing over time ● Due to both sea level rise and land subsiding Flori
