The Freezing of Supercooled Water

To investigate the freezing of supercooled water of high purity, measurements were made of the freezing point of samples of water in glass capillary tubes, both with and without a hydrophobic coating on the walls. These showed the difficulty of excluding freezing nuclei that originate in room air. A simple technique was therefore devised for preparing uncontaminated specimens of water in glass or fused silica tubes. Samples prepared in this way froze at temperatures consistently lower than any previously recorded for similar volumes of water. The lowest value obtained for water in glass was - 34 5°C for a volume of 6 × 10 -4 cm 3 . It is shown that some of the results of previous workers can be accounted for by the presence of foreign freezing nuclei in the water used. The relationship between volume and freezing point for spontaneous nucleation is discussed in the light of experimental results.