![constant pressure gas thermometer constant pressure gas thermometer](https://images.slideplayer.com/6/5661409/slides/slide_18.jpg)
If you extend the curves shown in figure toward negative temperatures, you find, in every case, that the pressure is zero when the temperatures is –273.15☌. Experiments show that the thermometer readings are nearly independent of the type of gas used as long as the gas pressure is low and the temperature is well above the point at which the gas liquefies. The line connecting them serves as a calibration curve for unknown temperatures. The two dots represent the two reference temperatures namely, the ice and steam points of water. The pressure versus temperature graph for a typical gas taken with a constant volume is shown in figure. The physical property used by the constant volume gas thermometer is the change in pressure of a gas at constant volume. The constant volume gas Thermometer and the absolute temperature scale The gas thermometer used in the next article meets this requirement. To surmount this problem, we need a universal thermometer whose readings are independent of the substance used in it. This discrepancies between thermometers are especially large at temperatures far from the calibration points. When one thermometer reads a temperature, for example 40☌ the other may indicate a slightly different value. A practical problem in this type of thermometer is that readings may vary for two different liquids. Thus, each segment denotes a change in temperature of one Celsius degree (1☌). Once the liquid levels in the thermometer have been established at these two points, the distance between the two points is divided into 100 equal segments to create the Celsius scale. On the Celsius temperature scale, a thermometer is usually calibrated between 0☌ (called the ice point of water) and 100☌ (called the steam point of water). The thermometer can be calibrated accordingly. Any temperature change is proportional to the change in length of the liquid column. In this case the physical property is the change in volume of the liquid. (5) the electric resistance of a conductor.Ī common thermometer in everyday used consists of a mass of liquid, usually mercury or alcohol that expands in a glass capillary tube when heated. (4) the volume of a gas at constant pressure and (3) the pressure of a gas at constant volume Some physical properties that change with temperature are All thermometers are based on the principle that some physical properties of a system change as the system’s temperature changes. Thermometers are devices that are used to measure temperatures. Thermometers and the Celsius Temperature scale The title Baron Kelvin was given in honor of his achievements, and named after the River Kelvin, which flowed past his university in Glasgow, Scotland. He is widely known for developing the Kelvin scale of absolute temperature measurement. He did important work in the mathematical analysis of electricity and thermodynamics, and did much to unify the emerging discipline of physics in its modern form.
![constant pressure gas thermometer constant pressure gas thermometer](https://www.aticoexport.com/wp-content/uploads/2014/01/Constant-Pressure-Air-Thermometer.jpg)
William Thomson, 1 st Baron Kelvin, ( 1824 – 1907) was a British mathematical physicist, engineer, and outstanding leader in the physical sciences of the 19th century.