Mercury thermometer which parameters need correction, correction method is what?

Thermometer is a common measurement tools, because of its readings are susceptible to error caused by the influence of many factors, therefore, to obtain accurate temperature data, must be carried out on the thermometer for correction. Thermometer readings correction of ordinary thermometer calibration is carved on the thermometer all under the condition of uniform heat. But we often only will be part of the thermometer inserted in the determination of temperature hydrothermal, there was a water line dew outside the liquid level, such determination of the temperature lower than the results obtained all immersed in a liquid thermometer. To accurately measure the temperature, therefore, must be on the leakage of water line caused by the error correction. Commercially thermometer scale calibration, thermometer, the calibration may not, in use process, cyclical heating and cooling, can also lead to changes in the thermometer zero, and affect the results of the determination, so also must carry on the correction, the correction as the thermometer calibration correction. If the thermometer calibration correction, then don't have to make correction of reading. The thermometer calibration correction is usually there are two ways: ( 1) The melting point of pure organic compounds as a standard to choose several known melting point of pure organic compounds, the thermometer is used to test their melting point, with the melting point of the measured temperature as ordinate, the observed melting point and the known material melting point of difference as the abscissa, draw the calibration curve. So anyone who use the thermometer measured temperature can be found by the curve correction values. Commonly used thermometer calibration standard compounds are: ice - Water ( 0℃） , diphenylamine ( 53℃） And benzoic acid ( 122℃） 。 ( 2) Compared with standard thermometer will standard thermometer and correction thermometer in parallel in a hot bath, slow uniform heating, every 5 ℃, respectively, to write down the two thermometer readings, mark the deviation value Δ t, Δ correction for the temperature of the thermometer - t = Standard thermometer temperature, and then for the correction of the temperature of the thermometer as ordinate Δ t as the abscissa, draw the calibration curves for correction.