Thermometers are of various kinds for different needs and uses:
Before the invention of the ear thermometer – readings were possible only through the mouth, underarm or rectum. If any doctor wanted to record the brain temperature accurately – they used electrodes to be attached to the patient’s hypothalamus.
This was done by an infrared probe where the tympanic thermometer has a projection which is placed in the ear gently after which a button is pressed. As a result the temperature is recorded within the span of a second. You will see that thermometers of these kind are available both for medical and home uses.
To some extent the readings of this thermometer are unreliable – if the placement in the year was faulty and one places it in the external ear canal by the operator or any wax that may be blocking the canal. Sometimes due to this a fever may not be detected.
This kind of thermometer is a band and is used to the patient’s brow. It is a thermometer type that contains liquid crystals that are highly sensitive and are in a plastic strip. These bands or strips change color to measure and detect different temperatures.
When the temperature changes it affects the color of the liquid crystal in the making them useful and ready for recording temperature.
Some people even make disposable liquid crystal thermometer at home and also for medical use. For instance a black thermometer can change color when placed on the forehead.
The thermometers that use liquid crystals have two stages:
- Nematic stage – that is hot and closest to the liquid phase – here the molecules tend to move freely and are ordered partly.
- Smectic Stage is the hot stage and is closest to the solid phase – here the molecules tend to align themselves into tightly wound chiral matrixes.
The thermometers that are made of liquid crystals show temperatures in the form of colors caused by changes in heat flow. They observe if the heat is flowing due to radiation, convection or conduction.
In cases of medical applications thermometers with liquid crystals are used in order to read the body temperature and used by placing them against the forehead of the patient. It is considered much more safe than a thermometer that has mercury in a glass.
Another areas where liquid thermometers are used are aquariums and in mood rings. He person who invented the liquid crystal thermometers is Bob Parker in California.
Temporal Artery thermometer
This kind of thermometer is used by the principle of the infrared temperature. One is advised caution as these thermometers are not considered to show accurate results.
Electronic clinical Thermometer
Electronic thermometers have been used since inexpensive methods of measuring temperatures and displaying them have started becoming available. Many of these thermometers display accurate reading to great precision – yet cannot be taken as guarantee of precision.
Once should check the specified accuracy by documenting and maintaining the temperature recorded by electronic thermometers by periodical recalibration. The first electronic clinical thermometer was invented way back in 1954 containing a Carboloy thermistor that used a flexible probe.