Measurement of temperature

The thermodynamic temperature scale

The thermodynamic temperature scale One of the difficulties in the accurate measurement of temperature is that the various types of thermometer, e.g., mercury-in-glass, platinum resistance, therm electric, and so on give different readings when used to measure the same temperature, because the value obtained depends on the properties of the substance used in the thermometer. It was not …

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Six’s maximum and minimum thermometer

Six’s maximum and minimum thermometer This thermometer is popular among gardeners for use in greenhouses. Its purpose is to record the maximum and minimum temperatures reached since the thermometer was last read. Generally speaking, a minimum temperature occurs during the night and a maximum during the day. Invented by James Six towards the end of the eighteenth century, …

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To measure temperatures with the thermometer

To measure temperatures with the thermometer When a Celsius thermometer is graduated in a factory the stem between the two fixed points is divided into 100 equal parts by means of a special dividing engine. This is generally beyond the resources of the ordinary laboratory, but the thermometer may still be used to measure an unknown temperature …

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Determination of the upper fixed point

Determination of the upper fixed point This is done by pushing the thermometer through a hole in a cork and placing inside a double-walled copper vessel called a hygrometer (Fig. 14.2). Water is steal boiled in the lower part of the hygrometer, thus keeping the bulb surrounded pure water vapor at atmospheric pressure. For reasons already mentioned,  important …

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