Homework #1 Glaciology, GEOL 4888, Spring 2022 Humphrey

1. Draw, by hand but carefully, a diagram of the molecular arrangement in an ice crystal (Ice Ih). Include at least 18 oxygens, and adjoining hydrogens. You can draw circles for the atoms, slightly bigger for the oxygens, and lines or dotted lines for the actual bonds.

-Include one Bernal-Fowler defect of each type (+ & - H).

-Label the c-axis direction and the a-axis directions.

-Outline a ‘puckered ring’ and a ‘boat’ shaped hex ring (and label them).

If you do this diagram carefully, you should be able to see the ‘puckered-ring’ structure of the basal plane oxygens and the ‘boat-like’ structure of the oxygens in the c-axis direction.

2. Just because it will make you look carefully at the ice structure, try to visualize the difference between ice 1h (hexagonal ice) and ice 1c (cubic ice, only found below about -80C). You will have to surf the web for images. Can you state in words, what is the difference between these 2 forms of ice?

3. And to drive home the thermodynamics of water and ice that we have been working with: What percentage of ice froze in the plastic bottles I shook in class. The water was at -6.5C. The heat capacity of water is 4,200 Joules/Kg C, the latent heat of fusion is 333000 J/kg. (that is all you need to know, but if you want, the bottle was a 0.5liter [.5Kg] bottle)