Physical Properties
Mercury cannot be used below the temperature at which it becomes solid, -38.83 °C (-37.89 °F). If the thermometer contains nitrogen, the gas may flow down into the column when the mercury solidifies and be trapped there when the temperature rises, making the thermometer unusable until returned to the factory for reconditioning. To avoid this, some weather services require that all mercury-in-glass thermometers be brought indoors when the temperature falls to -37 °C (-34.6 °F). To measure lower meteorological temperatures, a thermometer containing a mercury-thallium alloy which does not solidify until the temperature drops to -61.1 °C (-78 °F) may be used.
Read more about this topic: Mercury-in-glass Thermometer
Famous quotes containing the words physical and/or properties:
“The axioms of physics translate the laws of ethics. Thus, “the whole is greater than its part;” “reaction is equal to action;” “the smallest weight may be made to lift the greatest, the difference of weight being compensated by time;” and many the like propositions, which have an ethical as well as physical sense. These propositions have a much more extensive and universal sense when applied to human life, than when confined to technical use.”
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