SM149     Retardation of solidification demonstration     circa 1930     Heat

  The special thermometer incorporating a quantity of pure water around the bulb is used to show that water can still remain liquid if cooled slowly without agitation at a temperature well below zero degrees Celsius.   This temperature can be as low as minus 15 deg C.   When the water is then shaken it at once solidifies.

  The demonstration consists of cooling the water by means of dropping ether on to the bulb and reusing the cooled unevaporated ether thus cooling the water to about – 6 deg C.    The water will remain liquid until it solidifies on mechanical agitation of the bulb containing it.