What is the accuracy of laboratory thermometers

Thermometers are devices that allow us to measure the temperature of an object, person, animal, material, food, environment ... For any type of measurement that we have to perform, we have a different type of thermometer. Within the thermometers, we can also find different formats: mainly analog and digital.

When it comes to measuring the temperature of a food when we are cooking it, a test in a laboratory or in any other situation where it is necessary to know the temperature precisely, we cannot use traditional thermometers, but we are forced to use laboratory thermometers.

What is a laboratory thermometer

As I mentioned in the previous paragraph, laboratory thermometers, which they are mostly digital allows us to measure the temperature accurately, since this is a very relevant part, especially when it is necessary to maintain it in order to carry out the project we are doing.

This type of thermometer offers us a measurement scale that may vary by manufacturer and model, so we must take it into account when looking for the laboratory thermometer that meets our needs, both present and future if we want to extend its use to future projects.

The best laboratory thermometers

If you want to acquire a good laboratory thermometer, you can take a look at these models that we recommend:

King Scientific

King Scientific has several analog laboratory thermometers like this one, a glass thermometer that is capable of reliably measuring from -50ºF to 122ºF temperature. It is not expensive at all, and measures about 30 cm in length, which is ideal if the experiment is dangerous, so you don't have to put your hand too close.

Thermometer World

For a fairly affordable price you have this two-piece set. Two glass thermometers with a stainless steel ball to use as a handle. They are 30 cm long and It can measure from -10 to 50ºC. Ideal if you are going to carry out two experiments simultaneously so you don't have to waste time washing it to use it in the other experiment...

GEAL ZH Lt. L0130/10

It is another glass alternative from this brand. Graduate with Celsius degree scale, good quality and precision. In this case, it can have variations of only 0.5 degrees. It is 305mm long and comes in a protective case.

This model comes from the -10ºC to +50ºC. A fairly small range, but since it is long, you will be able to detect even very small variations.

Thermometer World

This other model of glass thermometer is a good option both for measuring temperatures for making wine or home beer, or for scientific laboratories. A model manufactured in the United Kingdom, and with a length of 155 mm.

The range of temperatures between -10ºC and 110ºC. It has great quality, precision and has been created to meet the highest standards to satisfy customers.

Text 108

It is a more advanced laboratory thermometer. Testo provides a digital model that can measure temperature thanks to its steel probe and display the result quickly on its screen. In this case it is more sensitive than in the previous cases.

It is ideal for the food industry, to control temperature, with connectable type K and T probes. In addition, it has protection against dirt and splashes of type IP67, and is certified by HACCP and EN 13485.

How are laboratory thermometers

Laboratory thermometers, although their name may indicate that they are special objects, Nothing further from reality. These types of thermometers offer us the same design that we can find in traditional mercury / gallium thermometers if we talk about analog thermometers.

Analog thermometers are shaped like long glass tube with a bulb at one end where is the substance that will allow us to measure the temperature and that will change shape depending on the temperature of the object we are measuring.

Although most of the laboratory thermometers that we can find in Europe offers us the measurement in degrees CelsiusSome also incorporate Fahrenheit and Kelvin scales.

Digital thermometers, unlike those used to measure body temperature, have a more compact size, in the shape of a square and to which we must connect measurement sensor. These thermometers incorporate a screen where the temperature is shown on the scale that we have previously established: Celsius, Fahrenheit or Kelvin.

Parts of a laboratory thermometer

Analog laboratory thermometers are made up of a glass tube where the measurements it offers are shown. Inside, we find a capillary through which the liquid used to carry out the measurement circulates (gallium / galinstan or colored alcohol). Finally, we find the bulb, the lower part of the thermometer where the liquid used to measure is located.

Digital thermometers, as their name indicates, are electronic devices that includes a probe that can vary in length where we find the sensor to carry out the measurements. This sensor sends an electrical signal to the central unit, which will be in charge of interpreting it to offer the data we are looking for.

Unlike analog thermometers, digital thermometers are powered by a battery, a battery that must always be in good condition if we do not want to make erroneous measurements that could ruin our already laboratory, culinary project ...

Accuracy of laboratory thermometers

If you are looking for very precise laboratory thermometers, the most it is advisable to opt for a digital thermometerAlthough due to its high cost, it is likely to get out of our pockets, as long as we are considering a quality model with the certifications that ensure proper operation and accurate measurements.

This type of thermometers they are always the fastestHowever, they are not advisable when we have to make a measurement to a very hot or very cold object, especially if the measurement cable is extremely short.

In these cases, the best option is to opt for a glass laboratory thermometer, thermometers that in most cases, exceed 30 cm long so we avoid the risk of bringing the hand too close to the object we want to measure.

What characteristics should a laboratory thermometer have?

The characteristics of these thermometers They are not far from those of other thermometers. They just have to be safe and reliable to work with in a laboratory environment. In general, what scientists are looking for is a thermometer that is reliable (does not deviate too much from the actual temperature), robust (to withstand the conditions of the experiment), stable (does not oscillate too much in its measurements due to the environmental conditions of the experiment). experiment), and with good sensitivity (that can be sensitive to very slight changes in temperature).

Laboratory thermometer care

If you have several laboratory thermometers, you should tag them and have them well identified by their characteristics. Once you have them catalogued, the care you should take with them will largely depend on the type of experiments you do.

For example, if you immerse them in some type of chemical or solution, it is It is important that you maintain a good washing policy. You will likely then reuse it for another solution, and if those chemicals react, the remains could do so and throw off your experiment or contaminate the new sample, obtaining undesired results.

If it is digital, make sure it is washable. If not, you just have to clean the probe that you used in the experiment. The normal thing is to clean it with isopropyl alcohol or soap and water. Once clean, store the thermometer in a protective case and a safe place. They should not be in direct contact with sunlight. And if you have children, make sure to keep the batteries out of their reach…

If you are going to subject it to extreme temperatures, make sure that these temperatures are within the range supported by the thermometer you have purchased, otherwise it may not resist or may not take correct measurements.

Another case is if you are going to use it inside shakers or other types of devices where it can be hit and broken. In these cases you must properly hold the thermometer and protect it correctly so that it does not break, especially if it is made of galinstan or mercury, since it could break and the liquid come out, mixing with the solution or element of your experiment and causing an accident.

Calibrate a laboratory thermometer

As I mentioned in the previous section, laboratory thermometers, both digital and analog, are very accurate, as long as they have been manufactured by companies that have been previously certified by the National Accreditation Entity (ENAC).

It is not the same to obtain a wrong temperature measurement in a home experiment than a wrong measurement in an experiment, because if it is wrong, the whole project can go to waste and having to start from the beginning.

When buying a laboratory thermometer, we must take into account the manufacturer's certifications, if we want the measurements to be as faithful to reality with a minimum margin of error, a margin of error than in the case of an experiment laboratory, we must report on results.

Each laboratory thermometer must include allowable margins of error, margins of error ranging from 0,5º C, up to 2º C in addition to 1º C. These margins of error should be included in the results of the experiment.

If the thermometer is always going to be used to perform measurements under normal conditions, it is not necessary to calibrate it every so often. If, on the other hand, it is subjected to inappropriate temperatures for long periods of time, we should consider calibrating the thermometer once a year.

How to calibrate a thermometer

There are two methods for calibrating thermometers: by comparison and by fixed points.

Calibration by comparison consists of comparing the reading of the thermometer to be calibrated with the reading of a thermometer whose characteristics are known. This calibration method is based on Zeroth's Law. Zeroth's Law states that if two systems are in term equilibrium, each of them having the same temperature as a third system, the two systems have the same temperature as each other.

Fixed point calibration. Fixed point calibration is carried out using fixed temperature points, such as ice water, since ice melts at 0ºC and freezes at the same temperature.