Definition and Types of Thermometers

Posted on

Thermometer Is? Here is a complete explanation of what a thermometer is, Functions, Sample Images, Types and How to Use It

A measuring instrument called a thermometer may be quite familiar in the community. Usually this tool is one of the medical equipment that is always available at home because the thermometer is a very helpful tool for measuring body temperature when you have a fever.

But did you know that although the functions are the same, this tool has different types? To help you understand what a thermometer is, here we review the various functions and types of thermometer types equipped with complete image examples.

Thermometer Is?


Before knowing more about any of the types of temperature measuring instruments on this one, you should first know the definition of what a thermometer is.

The definition of a thermometer is a tool used to measure temperature (temperature) or temperature changes in an object (body) and a certain room.

The temperature measure measured using a thermometer is expressed in units of degrees Celsius (°C). As for international units, the unit used is the Degree Kelvin (°K).

The celsius thermometer uses a size of 0 – 100 degrees celsius, while for the lower fixed point the fahrenheit thermometer is 32 oF with its upper fixed point 212 o F.

The types of liquids commonly used as thermometer fillers are mercury and alcohol. Meanwhile, water is not used to fill the thermometer because water is an ugly conductor of heat and the nature of water that will discuss glass walls so that the range of temperature to be measured is limited.

The word thermometer comes from the Latin thermo which means heat and meter which means to measure. The inventor of the thermometer was the scientist Galileo Galilei in 1593 through his research by making a simple water thermoscope as a temperature measurement.

This discovery was then developed by an Italian scientist named Santorio Santorio precisely in 1612 who succeeded in adding a numerical scale to galileo’s thermoscope.

The development of this body temperature measuring instrument continued until in 1654 a scientist named Grand Duke of Tuscany, Ferdinand II made a glass thermometer containing alcohol liquid.

Thermometer Part Section


The thermometer used in general is a thermometer that contains liquid substances, be it mercury or alcohol. In order to learn how to use the thermometer correctly, it’s a good idea to first learn what the parts of the thermometer are.

  • Glass Tube

This is the outermost part. Part of the thermometer contains the main components that make up the thermometer.

  • Glass pipe

This glass pipe is a thermometer part that contains a liquid substance, be it alcohol or mercury. It looks like a tube but flattened. Its function is as a forging of the expansion of liquid substances.

  • Liquid Substances That Fill the Thermometer

Previously it was mentioned a little about the liquid substance that fills the thermometer. This thermometer filler liquid is the most important component on the thermometer because it is a component that indicates the temperature degree of the object being measured.

  • Scale

This next section is in the form of stripes with numbers. Its function is to indicate the scale of temperature degrees of the measured object or objects. The greater the number indicated on the scale, the higher the temperature.

Kinds of Thermometers

Thermometers are divided into different types based on several categories. There are thermometers that are divided based on the scale shown which consists of a Celsius thermometer, Fahrenheit Thermometer, Reamur Thermometer and Kelvin Thermometer.

There are also types of thermometers that are divided based on the filling material. There are thermometers with liquid fillers, thermometers with solid substances and so on. Here is a thermometer containing a liquid substance which is the most common type of thermometer found.

Mercury Thermometer


This type of thermometer is a thermometer that contains mercury that is placed on a glass tube. This type of thermometer has the advantage of its regular expansion and easy to see because it is shiny.

Mercury is used to fill the thermometer because mercury is a good conductor of heat so that the body temperature to be measured is known faster.

But the disadvantage of this type is that it cannot be used to measure very low temperatures and toxic properties of the material. For example, a clinical thermometer measures body temperature.

Clinical Thermometer


Next is the clinical Thermometer. This tool is most often used to measure the temperature of a person / patient who is felt to be sick with fever. Clinical thermometers have a measuring area between 35.5 to 42°C. This tool is widely needed, especially in the health sector and the medical industry.

The most suitable type of thermometer for measuring human body temperature is an oral type clinical thermometer (inserted into the mouth). This is because the measurement of temperature on the human body through the mouth has more accurate results than other measurement methods.

Temperature measuring instruments are called thermometers with many variations and models according to function and technology. One of them is the clinical version used by doctors, nurses, and anyone who works in the health sector. You can also have this tool for the purpose of checking body temperature at home.

Digital Thermometer


A practical and easy-to-read temperature measuring instrument is a digital thermometer. Its function remains the same, which is to determine the temperature of an object such as room, air, body, water, and anything else.

The tool is also available to the public at an affordable price. According to an article written by, some types of digital thermometer variants that are commonly used, especially in the health (medical) sector, are ear digital thermometers, digital dot thermometers, and forehead thermometers.

Room Thermometer


The room temperature measuring instrument also uses a thermometer mounted on the wall. As the temperature rises, you see a kind of sign indicating the position of a certain number. This tool is sometimes coupled to a temperature control or air conditioner of the room.

Laboratory Thermometer


The image of the temperature measuring instrument that often appears is a thermometer for the laboratory. If you have ever held a practice in school. This tool uses glass with mercury and a measurement scale. The function of measuring the temperature of a liquid or solid object.

Infrared Thermometer


There is also an infrared thermometer that uses a light signal to find out the temperature of an object. The way to use it is that you point this tool and fire infrared. The result will appear indicating a certain temperature.

Thermometer Bimetal


A bimetallic thermometer is a type of thermometer whose material is made of two pieces of metal with different expansion coefficients that are glued into one part.

The bimetal thermometer itself comes from the word “Bimetal” which has two metals. The meaning of bi is two and metal is a characteristic of its meterial made of metal.

The working principle of the bimetallic thermometer is characterized by a change in the curvature of the direction of the metal. When the expansion coefficient is low, the bimetallic piece will curve towards the metal, and vice versa.

Besides being used as a tool to measure temperature, bimetallic thermometers are also often found used as components of car turn signals, electronic irons, and thermostats.

Thermometer Six Bellani


Thermometer six bellani may be rarely seen and used for the public except for research needs. The tool uses two scales consisting of alcohol and mercury. Its function is to understand the boiling and freezing points of an object.

Thermometer Alcohol


The next type is a thermometer in which it contains an alcohol liquid which at the same time functions as a temperature measuring medium. The advantage of this breed is that it is more thorough for small temperature changes due to its large expansion. The price of this alcohol thermometer is also much more affordable than the mercury type.

In addition, alcohol thermometers are made of non-toxic materials. Unfortunately, this type of thermometer has a low boiling point. Because it can not be used to measure high temperatures.

Read Also The Most Thorough Time Measuring Tool

Thermometer Function


The main function of the thermometer is to measure the temperature (temperature) on a person’s body and also the temperature in a certain room. What distinguishes between the functions of the thermometer is the temperature of the object to be measured. This is what then makes thermometers consist of a variety of different types.

The most commonly encountered function of a thermometer is to measure body temperature during illness. For how to use the thermometer itself, there are several ways, namely by putting it in the mouth, placed under the armpit and inserted into the rectum.

Each of these methods also has its advantages and disadvantages. One thing to note of these three ways of using thermometers is that the temperature for each use of each of them is at odds.

When used in the rectum, the temperature is 0.5 °C higher than the measurement temperature from the mouth. Meanwhile, for how to measure through the armpits, the temperature is 0.5 °C lower than the measurement by mouth.

How to Use a Thermometer

To use and read a thermometer today is not too difficult, especially because there are already types of digital thermometers and infrared thermometers.

How to use a digital and infrared thermometer is easier because the temperature measurement results have been directly displayed in the form of a number scale in the form of digital writing.

Then how does the thermometer work? On a digital thermometer you only need to turn on the thermometer then attach the light to the forehead or the part of the body you want to measure.

Then, when the temperature measurement is complete, it will usually be marked with a ‘beep’ sound. Then the thermometer can be taken and the measurement results can be read immediately.

As for how to use a mercury thermometer, alcohol or clinical thermometer, the trick is to attach the tip of the thermometer to the body area then wait until a ‘beep beep’ sound is heard. After that you just have to read the measurement scale shown.

In conclusion, a thermometer is a measuring instrument used to measure temperature or its changes. In everyday life, this tool is often used to measure body temperature when it is sick. The explanation of the thermometer above hopefully can be useful for you.


Leave a Reply

Your email address will not be published. Required fields are marked *