A liquid crystal thermometer is a tool used to measure temperature ranges and heat transfer patterns. The results are displayed via color changes in the cholesteric liquid material the liquid crystal thermometer is made from. These thermometers are used for a variety of applications, from reading the body temperature of a patient to making accurate measurements of liquid and air temperature ranges in chemical laboratories or breweries. The low cost of the instrument, coupled with the ability to accurately measure a wide range of temperatures, makes this thermometer an integral part of many manufacturing and medical processes.
As the ambient temperature rises and falls, the color of the cholesterol based cholesteric liquid changes along the strip. To read a liquid crystal thermometer, the user simply notices the color variation of the thermometer. In some cases, the thermometer is also marked off in degrees of temperature with numerical designations for increased accuracy of readings.
Liquid crystal thermometers are often used as equipment in processes such as home brewing of alcoholic beverages or in other chemical reactions which require regulated temperatures. One of the more common thermometer types in use today is an adhesive strip which attaches to the outer surface of bottles or laboratory equipment and produces accurate readings of the containers temperature. For operations such as micro brewing of beers, this thermometer gives an accurate measurement of the temperature range in the brewing container. While the measurement is not as precise as a laser thermometer or a traditional thermometer which is immersed in the liquid, the liquid crystal thermometer produces a result that has sufficient accuracy for reactions that must be kept in a certain temperature range, rather than a specific target temperature.
Hobbyists who keep tropical fish or exotic pets, such as reptiles and amphibians, have also adopted this type of thermometer as an important part of their equipment. Easily replaceable and low in cost, these thermometers can be attached to the outer surfaces of aquariums to provide an accurate measurement of the temperature ranges of the water or air inside. Unlike traditional mercury thermometers, the liquid crystal style of thermometer is not prone to breakage and the release of dangerous chemicals which could cause harm to the animals or fish in the tank.
In laboratory settings, the liquid crystal thermometer may be used to measure temperature changes and transfer patterns. The cholesterol based liquid of the thermometer can be used to effectively track the transfer of heat through convection, radiation and conduction. The same principles can also be used to demonstrate the cooling properties of liquids by heating the thermometer and then tracking how quickly the liquid lowers the temperature of the thermometer by evaporation or immersion.