Thermometers are made of thin glass tubes. The lower end of the pipe is bulged, filled with alcohol or mercury. The air in the elongated section with the streaks is discharged, then its mouth is closed. Thus, when the heat increases, the liquid in the tube expands and rises slowly.
Swedish physicist Anders Celcius (1701-1744) proposed a hundred »system for grading the thermometer; Today this system is used in many European countries and Turkey. Celcius first detected two points on the mercury thermometer: he marked the melting point of the ice as 0 and the boiling point as 100. Then divided 0 to 100 into 99 equal parts; these were called Celcius degrees. Then the printer thermometer (automatically records the temperature changes on a sheet) and the maximum and minimum thermometer (records the lowest and highest temperatures over a period of time).
THERMOMETERS WITH CIRCULAR AND SPIRIT
The measuring range of mercury and spirit thermometers, which are always sufficient to measure the encountered temperatures, is very narrow and limited. Different liquids such as toluene and pentane are used to measure lower temperatures. High temperatures are measured by gas thermometers. For very thin temperature measurements, electrical resistance thermometers and thermoelectric thermometers are used in laboratories.
With the nitrogen thermometer, temperatures up to 1600 ° C can be measured. Pyrometers are used to measure temperatures above this. This apparatus does not need to touch the object whose temperature is to be measured, it only needs to measure the radiation of the object.
The thermostat is a device that keeps the temperature constant in a closed environment based on the data of the thermometer. It has a knob that can be adjusted to achieve the desired temperature; the thermostat electrically connected to a heating device serves to increase or decrease the temperature delivered by the device.
In the 18th century, the heat was measured by a balloon filled with air. However, due to changes in atmospheric pressure, the information it gave was incorrect. XVII. Century, the first spirited thermometer was built in Florence. In 1721, the German physicist Fahrenheit produced the mercury thermometer. The thermometer used by the Anglo-Saxons today bears his name. In this thermometer, 32 ° F indicates the melting point of the ice; 212 ° F indicates the boiling point of water.