Thermometers measure temperature, by using materials that change in some way when they are heated or cooled. In a mercury or alcohol thermometer the liquid expands as it is heated and contracts when it is cooled, so the length of the liquid column is longer or shorter depending on the temperature. Modern thermometers are calibrated in standard temperature units such as Fahrenheit or Celsius. In today's society, taking your temperature can be as simple as the click of a button or it can be a little more time consuming with the thermometers that you place underneath the tongue and wait for the current temperature. The thermometers most commonly used are the digital thermometers that you place under the tongue. They are accurate and it doesn't take too long to get the temperature of the person. Still used is the thermometer in which you place under the tongue and guess on the temperature given the height of the red substance in the center of the glass cylinder. This can give you a pretty good idea of the current temperature, but it can't always be accurate. Finally, there is the newest digital thermometer in which you gently place the probe in the ear, push a button and the temperature of the person shows up in no time at all. With this technology and faster scanning methods, Digital Instant Ear Thermometers offer you the ultimate temperature-measuring tool. This is the most advanced thermometer of today's time.
History.
The first thermometers were called thermoscopes and while several inventors invented a version of the thermoscope at the same time, Italian inventor Santorio Santorio was the first inventor to put a numerical scale on the instrument. Galileo Galilei invented a rudimentary water thermometer in 1593 which, for the first time, allowed temperature variations to be measured. In 1714, Gabriel Fahrenheit invented the first mercury thermometer, the modern thermometer. By the time Thomas Clifford Allbutt was a young man, the thermometer was commonly used to monitor sick patients.
