In Sir William Thomson, Baron Kelvin of Largs, Lord Kelvin of Scotland — proposed the absolute temperature scale with zero degrees being the theoretical lowest temperature possible where molecular motion ceases.
Kelvin defined 1 Kelvin degree as being equal to one Celsius. Since it has been known simply as the kelvin K. Are you looking for any product in particular? We offer a vast array of thermometers for different temperature measurement across all sectors and a multitude of applications. Click here for industrial thermometers and instrumentation. Click here for scientific thermometers, educational products and accessories.
Click here for catering thermometers and accessories. Click here for thermometers for the home, greenhouse and garden. Click here for medical thermometers, including animal health products. Please contact us if you have a specific order or enquiry not listed above. Search for:. The thermoscope The predecessor to the thermometer — the thermoscope — is a thermometer without a scale; it indicates differences in temperature only i.
Medical thermometers are an essential aspect of the history of thermometers in general and predate Fahrenheit. Santorio created the first, but it was impractical in many ways. The first practical medical thermometer was created by Sir Thomas Allbutt, an English physician.
His invention was only 6 inches long and could accurately read a temperature in just five minutes. Jacob Fraden at Advanced Monitors Corporation, its CEO, who created in what is now the most widely used of ear thermometers, but that required digital thermometer technology. Like their predecessors, digital thermometers are temperature-sensing devices that are easily portable and have permanent probes.
The differences, however, are that the sensors are digital, and these devices usually have a convenient digital display. The way a digital thermometer works depends entirely on the type of sensor employed. Sensor types include resistance temperature detector or RTD, thermocouple and thermistor. Each type has advantages and disadvantages. Digital hygrometers, such as ThermoPro digital hygrometers , which are among the most popular on the market are used to measure the humidity—and in particular relative humidity—of air.
One must appreciate how the thermometer was invented to appreciate how the hygrometer was made, and they are often closely associated because of their combined use in meteorology and other sciences. RTDs are made up of wire windings that exhibit responses to temperature changes.
The hotter they are, the higher their electrical resistance, and that can be measured accurately. Thermocouples comprise a different pairing of metal wires that create a thermoelectric voltage. As the temperature changes, there is a near-immediate change in voltage, which can be measured. Thermistor elements are semiconductor devices that are highly sensitive due to the relationship between temperature and their electrical resistance.
There are two main types: negative temperature coefficient or NTC devices and positive temperature coefficient or PTC devices. Meat thermometers, such as those made by ThermoPro , are bimetallic thermometers. The early version of this thermometer contained alcohol and in Fahrenheit developed a mercury thermometer using the same scale. He assigned the freezing point of water at 32 degrees, the boiling point of water as degrees and the normal body temperature as Later on in that same century, the inventor Anders Celsius developed a numerical scale, called the Celsius or Centigrade scale.
This scale was based on a scale of zero to one hundred where the freezing point of water is zero, the boiling point of water is degrees and normal body temperature is 37 degrees.
The first real medical thermometer was invented by Sir Thomas Allbut in For almost a hundred years thermometers were basically unchanged.
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