The freezing bomb

摘要

The extreme pressures that are generated when water freezes weretraditionally demonstrated by sealing a small volume in a massive cast iron'bomb' and then surrounding it with a freezing mixture of ice and salt. Thisvessel would dramatically fail by brittle fracture, but no quantitativemeasurement of bursting pressure was available. Calculation suggests amaximum of about 55 MPa (8000 psi) might have been achieved, with some2.3% of the water frozen into a hollow shell around the interior of the vessel.In a sufficiently strong alloy steel container the pressure might rise to amaximum of 210 MPa (30460 psi), this limiting figure being due to thecollapse of ordinary ice (ice I) to the denser forms ice II or ice III.