Freeze fracture electron microscopy of an aqueous solution of glycerol (10%) frozen in a straw (0.25ml capacity). Ice was nucleated within the straw at -7°C. The sample was then cooled at c.1000°C per minute to -100°C and then transferred to liquid nitrogen. A cross fracture of the straw followed by deep etching reveals the structure of ice (etched areas) and of the freeze concentrated material (non-etched material). The distribution of the ice and freeze concentrated material is relatively uniform across the straw. The freeze concentrated material is not homogeneous in composition and contains many small ice crystals. Low power. For higher magnifications of this sample see the next pages. Also, compare with a cross fracture of a straw which has been frozen at a lower rate of cooling.
