Mercury in glass Thermometer and Phosphor Thermometer

Mercury in glass Thermometer

The mercury thermometer or mercury in glass thermometer was invented by Daniel Gabriel Fahrenheit in 1714. The mercury glass thermometer consists of a bulb and it contains mercury in it. And the tube is attached to the glass tube is of thin diameter. Compared to the bulb volume in the tube the mercury is very less. With change in the temperature the volume of the mercury changes. The small change in the volume efforts the thin mercury column a moderately long way up the tube.  The space present between the tube and mercury is filled with nitrogen. It is present at less than pencil vacuum and atmospheric pressure.


In order to adjust the thermometer, the bulb is prepared to reach the thermal equilibrium according to the temperature standards. They are water mixture or ice mixture, and other standards are water mixture or vapour mixture. Between the fixed point the tube is divided into the regular intervals.

By using different materials, thermometers are made. Due to different expansion properties they show different intermediate readings. In practice the substance used are chosen to have reasonably linear expansion characteristics as a function of thermodynamic temperature.


Uses of thermometer:

Physical effects are used by the thermometer to measure the temperature. The temperature sensors are used in wide variety of engineering and scientific applications mainly in case of the measuring system. The temperature system must be a mechanical or electrical, rarely inseparable from the system which they control.

Phosphor thermometer

This instrument is used for the measurement of the surface temperature. The method feats luminescence that is released by the phosphor material. Phosphor materials are of pastel colour or fine white inorganic residues which may be stirred by any of a variety of incomes to emit light.  Some features of the emitted light that change in this case including the temperature, colour, brightness, glow duration and the last one is used for the measurement of the temperature.

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