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11 Types of Thermometers




A thermometer is a device utilized to measure the temperatures of a body. It is a device found in almost every home and surely in all the healthcare centers. An ideal thermometer must have an extensive temperatures range. As no thermometer is ideal for every use, we have many thermometers used for different materials and uses. Let us discuss in detail about them:

Types of Thermometer

1. Clinical or Medical thermometers

A medical thermometer is used to measure body temperatures. Almost all thermometers made in the 20th century are mercury thermometers. This type of thermometer is sensitive and accurate. It has a narrow place where the level of mercury rises very fast. There is a kink on the tube that stops the mercury level from falling on its own.

It measures human body temperatures in the range of 35 °C to 42 °C. These thermometers are helpful in the clinics to the doctors, so they are also known as ‘doctor’s thermometers.’ It is mandatory to clean these medical thermometers with alcohol after each use so that infection does not spread from one patient to another.

2. Laboratory Thermometers

These are useful to measure the room temperatures of hot solids and liquids in experiments. Laboratory thermometer measures temperatures in the range of 5 °C to 110 °C and even higher temperatures.

3. Digital Thermometers

The digital thermometer measures the temperatures through an electronic circuit. All the information they capture passes to a microchip that processes the information and displays it numerically on the digital screen. These are fast, accurate, easy to use, and inexpensive. These advanced thermometers can measure the temperatures of a body at a high level of accuracy.

4. Infrared Ear Thermometers

The temperature in the ear, commonly known as the tympanic membrane temperature, can also help to know your body’s temperature. Ear thermometers measure the temperature by using the inner part of your ear. This type is preferable for children as it measures the temperature quickly. The ear thermometer is very fast and easy to read. But, one should not over-squeeze the infrared thermometer in the ears with a lot of wax.

An infrared thermometer captures body heat in the form of infrared energy supplied by a heat source. This type of thermometer works on the laws that govern the radioactive emission of bodies. This emission allows the precise calculation of the radiating object’s temperature from its emission spectrum without requiring direct contact.

5. Mercury Thermometers

It has linear expansion properties, ranging from -35°C to +500 °C (with compressed nitrogen). The mercury thermometer is not in use due to health risks like respiratory problems or skin damage. But, currently, glass thermometers have replaced the old mercury thermometers, called analog thermometers. This thermometer does not have mercury in its composition, making it safe to use. This type of thermometer usually takes longer to measure the temperature, and the reading is also more challenging to understand.

6. Alcohol in Glass Thermometers

It displays the temperature from the sealed glass of the level at which mercury or alcohol reaches a graduated scale. Those liquids dilate and contract according to changes in temperature. In general, the measurement scale users use is Celsius. One can also express it in degrees Fahrenheit. These thermometers currently consist of colored alcohol due to the danger of contact with mercury.

7. Constant Pressure Gas Thermometers

This type of thermometer can operate at both constant volume and constant pressure. They have an exact measurement system and are often helpful in adjusting other thermometers.

Here, the volume increases directly with the increase in temperature. This thermometer measures temperature in the range of 0 K 500 K.

8. Platinum Resistance Thermometers

These thermometers measure the temperature through a platinum wire attached to an electrical resistance that changes according to the temperature. Generally used to measure outside temperatures, it is very accurate but slow.

In this thermometer, resistance of the material increases directly with an increase in temperature. It measures temperature in the range of 500K to 2300 K.

9. Thermocouple Thermometers

These thermometers measure the temperature quickly and are generally useful in laboratories. They measure the temperature through an electrical resistance generating a voltage that changes according to the connection temperature.

10. Pyrometer Thermometers

This measures the temperature through the heat radiation emitted by the objects. One does not need to touch objects to know their temperature. It measures them while the objects are moving, are far away, or when their temperatures are very high.

11. Pacifier Thermometers

They are suitable instruments for measuring the temperatures of infants as they take the temperature without causing any discomfort. One can use this in the same way as the standard digital thermometer for oral temperature.

Thermometers are the essential requirement for diagnosing any diseases. Different types of thermometers are helpful for different purposes. Before using it, one should have proper knowledge about the types, applications, and temperature capacity of any thermometer.

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