Thermometer, accuracy recording

Temperature Recording. Use an accurate temperature-sensing device, such as a clinical thermometer or thermistor or similar probe, that has been calibrated to ensure an accuracy of 0.1° and has been tested to determine that a maximum reading is reached in less than 5 min. Insert the temperature-sensing probe into the rectum of the test rabbit to a depth of not less than 7.5 cm and, after a period of time not less than that previously determined as sufficient, record the rabbit s temperature. 

Viscosity depends on temperature. The higher the temperature, the lower the viscosity Pancake syrup, for example, flows more freely when heated. For reasonable accuracy when measuring viscosity, the temperature must be very carefully controlled. This means that the viscometer and sample must be immersed in a constant temperature bath and the temperature given time to equilibrate before the measurement is recorded. A calibrated thermometer must be used to measure the temperature. 

To test for temperature accuracy of a column oven, one should place the temperature probe/sensor of a calibrated/verified electronic thermometer (with at least 0.5°C precision) into the oven. The probe/sensor should not make contact with anything inside the oven. With the oven door closed, allow the temperature to stabilize for at least 20 min at each tested temperature (e.g., 30, 45 and 60°C). The thermometer s temperature should then be recorded at each temperature. The difference between the actual and set temperature should typically be within 1°C. 

The accuracy of the melting point depends on the accuracy of the thermometer, so the first exercise in this experiment will be to calibrate the thermometer. Melting points of pure, known compounds will be determined and deviations recorded so that a correction can be applied to future melting points. Be forewarned, however, that the thermometers are usually fairly accurate. 

The determinations arrived at in this manner are employed in making corrections. If the variation is less than 0.5° it may be neglected, as the accuracy of ordinary thermometer scales is limited to this difference. If, however, the variation exceeds 0.5°, it must be taken into account, and the necessary correction is added or subtracted from the observed temperature. In this case it is assumed that the bore of the capillary is uniform throughout. For example, assume that the zero point is found to be - -0.7°, while the 100° point shows no variation. It is obvious that the reading at any intermediate temperature will vary from that observed by a proportionate amount. Thus, if the temperature recorded by the... 

On account of the mechanical construction of pressure thermometers, both as regards the mechanism for indicating and recording and the necessity for using comparatively large and heavy bulbs, the accuracy that can be secured with this type... 

Calibration of a DTA involves adjustment of instrumental electronics, handling and manipulation of the data in order to ensure the accuracy of the measured quantities temperature, heat capacity and enthalpy [614,615,621]. Temperature sensors such as thermocouples, resistivity thermometers or thermistors may experience drifts that affect the mathematical relationship between the voltage or resistance and the absolute temperature. Also, significant differences between the true internal temperature of a sample with poor thermal conductivity and the temperature recorded by a probe in contact with the sample cup can develop when the sample is subjected to faster temperature scans. The important quantity measured in DTA experiments is the AT output from which enthalpy or heat capacity information is extracted. The proportionality constant must thus be determined using a known enthalpy or heat capacity - the power-compensated DSC requires lower attentiveness as it works already in units of power. The factors such as mass of the specimen, its form and placement, interfaces and surface within the sample and at its contact to holder, atmosphere... 

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