How to choose the best thermometer: what you needed to know

Thermometers are measuring instruments, designed with the purpose of taking the temperature through various scales and mechanisms. At first one of the mechanisms used was expansion, since this is one of the properties of certain materials to be able to expand in the presence of heat, common among metals and various substances such as alcohols.

 

In the evolution of medical technology, the thermometer represented an important advance since it allowed the measurement of the temperature of the human body and accurately measure symptoms such as fever, however now thermometers are not only used in medicine.

 

Just as it is possible to find different types of thermometers, it is also possible to find different measurement scales for these, some are Celsius, Fahrenheit, Kelvin and Reaumur. In the following article we show you everything you need to know about thermometers, as well as speed up your selection and purchase process with the purchase links of all the models we have for you.

 

Thermometers, characteristics, types and uses

 

As we have shown you previously, there are different types of thermometers with their respective characteristics, uses, advantages and disadvantages. Below we have listed each and every one of the existing types, along with their purchase links and suggestions. Keep reading, you might be interested.

 

1- Of mercury

 

Mercury thermometers were created in the year 1714 by a physicist and engineer with the surname Fahrenheit, that's where the scale measure used comes from. The Mercury thermometer consists of a bulb from which a thin glass tube extends and inside is liquid Mercury, however the volume of this metal is less than the total volume of the bulb.

 

It is necessary to inform you that the Mercury thermometers are being replaced little by little by those that contain Gallium or Galinstane inside. Meet some models here .

 

Advantage

 

·         Despite the toxicity of mercury, its use will allow you to determine the temperature with greater precision compared to other liquids.

·         Mercury thermometers tend to be much more durable under duress.

·         Their prices are the lowest.

 

Disadvantages

 

·         If your Mercury thermometer falls, inhaling the Mercury will turn it into a toxic vapor to inhale. Therefore, you must collect it immediately using rags, gloves and masks as well as you must ventilate the room.

·         Mercury has a low freezing point in relation to alcohol; as a consequence it cannot be used in colder areas.

·         They are not recommended for use in babies and young children.

 

2- Laboratory

 

Laboratory thermometers are measuring instruments with which the temperatures of different liquid or gaseous substances can be determined, their accuracy and precision characterize them since they are superior to other commercial thermometers.

 

In other words, laboratory thermometers are designed to determine the magnitude of vibratory energy presented by the molecules of a substance. This energy is manifested in heat, its intensity is determined by a specific value of temperature. Check out some models here.

 

Advantage

 

·         The laboratory thermometer is characterized by having a high sensitivity thanks to its fine bulb.

·         Temperatures between -10 degrees Celsius and 200 degrees Celsius can be determined, although there are some models that reach approximately 357 degrees Celsius.

·         Models can be found that measure temperature in Celsius, Fahrenheit, and even Kelvin.

·         They are designed to be resistant to temperature fluctuations.

 

Disadvantages

 

·         Laboratory thermometers are designed for industrial use.

·         If the thermometer is inserted into containers, it should not touch the edges or the bottom, it could reflect the wrong temperature.

 

3- Infrared

 

Infrared thermometers are equipment that allows the measurement of temperature in a professional way. They stand out from the rest for their ability to measure in the distance and without maintaining any contact with the object to be measured.

 

Some measurements that should be taken into account before acquiring one of these thermometers is to know the field of vision it contains, the emissivity of the object and of course the precision of its measurement. Some models available here .

 

Advantage

 

·         Infrared thermometers provide great reliability and speed when measuring temperature.

·         It offers ease of use.

·         You do not need to get close to the object to measure the temperature.

 

Disadvantages

 

·         If the surface of the object does not fill completely the reading will be wrong, since the infrared thermometer takes into account the surface of what is around the object.

·         Its price is very high.

·         Measurements with infrared thermometers cannot be performed in the presence of liquids and vapors as the measurement is altered.

 

4- Digital

 

·         Digital thermometers operate on the basis of specialized electronic circuits and sensors, they are capable of measuring the smallest voltage variations and translating them into digits within temperature ranges, generally Celsius and Fahrenheit are used. Learn more here .

 

Advantage

 

·         Digital thermometers offer precision that allows reliability when making measurements.

·         They have displays or screens in which the temperature can be observed from afar, which makes the measurement simple and attractive.

·         They are safe, resistant and light instruments.

 

Disadvantages

 

·         Measurements with digital thermometers can only be made between -39 degrees Celsius and 357 degrees since its melting point below this temperature makes Mercury solid.

·         Although they have great resistance, they can be classified as fragile instruments, they break easily.

·         They are not designed to withstand sudden changes in temperature.

·         For its use you must purchase batteries, once these are used up it is difficult to find their replacements.

 

5- Environmental

 

·         Environmental thermometers are those capable of measuring the ambient temperature of an open or closed environment by means of an internal sensor or an external probe, it can be used to control the temperature in rooms and in turn outdoors since they are manufactured in a way that they are resistant to the harshest conditions such as rain, wind, cold and very high temperatures. Some models available here .

 

Advantage

 

·         It is possible to find them under two formats, analog and digital.

·         Disadvantages

 

Accuracy can vary greatly between each type of format.

 

6- Gas

 

This class of thermometers are very accurate in their measurements, they have a very wide measurement range that includes from -27 degrees Celsius and 1477 degrees Celsius, however their use is more complicated, they are used mainly as normative instruments for the graduation of other thermometers.

 

Gas thermometers are made up of an ampoule with gas that can be Helium, Hydrogen and even Nitrogen according to the desired temperature ranges and a pressure measuring manometer.

 

To carry out the measurements, the gas bulb is placed in the environment whose temperature is to be measured, the column of the manometer that usually contains Mercury is adjusted whose function will be to give a fixed volume to the gas, the height of the Mercury column will indicate the gas pressure, from this point the temperature can be calculated. Learn more here .

 

Advantage

 

·         The measurement they offer is very accurate.

·         Its scope of application is very wide.

 

Disadvantages

 

·         Its high cost makes it the least purchased on the market.

·         It is used only as a normative instrument for the graduation of other thermometers.

 

7- Resistance

 

·         Resistance thermometers are sensors that measure temperature based on the way the electrical resistance changes in a conductor, which can be metal, electrolyte or semiconductor in relation to its temperature. The most popular of the thermometers is the Platinum one. Learn more here .

 

Advantage

 

·         Temperature measurement by platinum resistance thermometer is easier compared to gas thermometer.

·         These thermometers have a wide measuring range, from 200 degrees centigrade to 1200 degrees centigrade.

 

Disadvantages

 

·         Resistance thermometer readings give it slow.

·         They are very sensitive.

 

8- Industrial

 

Industrial thermometers work according to the principle of gas expansion, by expansion of a bimetal or by the expansion of a liquid, as well as being able to measure temperatures in wide ranges between 200 degrees Celsius and over 700 degrees Celsius.

 

These classes of thermometers are in danger of extinction because the digital versions of these instruments have been occupying their place for some time, due to their ease and simplicity of handling and use. Some models available here .

 

Advantage

 

·         It is possible to find them under two modalities, rigid bulb and capillary.

·         Temperatures above 700 degrees Celsius can be measured.

 

Disadvantages

 

·         Industrial thermometers are calibrated to measure very high Remote Reading thermometer.

 

9- Of alcohol

 

Alcohol thermometers are glass capillary tubes with a very small inside diameter that can be similar to the thickness of a hair, they have very thick walls, at one end there is a dilation called a bulb that is filled with alcohol.

 

Alcohol is a capable substance that expands or contracts due to changes in temperature, thus increasing or decreasing depending on it. A scale has been established on the tube that accurately marks the temperature of the body evaluated. This type of thermometer was one of the first to be created. Learn more here .

 

Advantage

 

·         The reliability of its measurement is high.

·         It is safer than Mercury thermometers.

 

Disadvantages

 

·         Alcohol thermometers are used to take the temperature of the environment but not in people.

 

10- Kitchen (For ovens)

 

Kitchen thermometers are very practical tools to control the exact cooking point of food and even the temperature of oils for the cooking process. Kitchen thermometers are specialists in determining the exact point of meats and roasts, and with these the process of creating candies, fried foods, chocolates and creams is improved.

 

Advantage

 

·         They offer great precision in their measurements, therefore it is possible to avoid that the food is very dry or hard and raw.

·         With the use of kitchen thermometers you can be sure that you have eliminated all the bacteria that food may contain.

·         You can find different models such as meat, digital, for ovens, and kitchen laser.

 

Disadvantages

 

·         They can only be used in food processing.

·         Its prices are high but it is justified with the utility offered.

 

11- Glass

 

Glass thermometers are also known as rod thermometers, they can generally include a metal sleeve of approximately 10 mm in outside diameter and a ring at its upper end that allows the instrument to be hung.

 

Advantage

 

·         These thermometers have great precision, between + - 1%.

·         The scratch of the scale on the thermometer is totally resistant to acids and alkalis.

·         They are inexpensive instruments that measure the temperatures of liquids and gases.

·         They do not need a source of energy for their operation.

 

Disadvantages

 

·         Glass thermometers must be treated with care, they must not be hit against any hard surface, since cracks may occur that would affect their accuracy.

·         Its maximum reading is approximately 354 degrees Celsius.

 

Thermometer parts

 

Thermometers, regardless of their type, have fundamental parts for their correct operation, below we will show you their parts explicitly.

 

·         Bulb: It is considered the base of the thermometer, it is located at the bottom, it is cylindrical or spherical depending on its supplier, they are usually made of stainless steel but some models can be made of glass.

·         Capillary: It is also known as a stem, it is the tube through which the Mercury or any of the substances mentioned above flows, it is inside the glass body of the thermometer and is in turn connected to the bulb. The size of this affects the measurement.

·         Body: The body is the glass tube that covers the capillary or stem, it is elongated and triangular in shape but the edges are smoothed, improving its handling, they can usually measure between 20 and 30 cm.

·         Expansion compartment: This is the space found above the stem, there the gas and air are deposited while the Mercury or the substances in your thermometer rise.

·         Scale: This includes the marks found on the body of the thermometer in which the temperature levels are indicated. Depending on the type of thermometer it can be found in Fahrenheit or Celsius.

·         Valve: The valve works as a connection between the bulb and the stem, this is the cause for the internal substance to drop slowly, giving the person the necessary time to read the temperature reached.