Depends on some circumstances: how far from the nearest star to throw? And what does “show” mean? shall we wait until its reading becomes constant over time? If not, how long does it take for a reading to be taken that is constantly changing over time? If completely in interstellar space, it will cool at a decreasing cooling rate.

I remember how, back in my first year, in physics classes, we solved simple problems where we derived a function (graph) of temperature versus time under precisely such conditions - in a complete vacuum, with no other sources of radiation. It’s not convenient to write formulas here; if you describe it, it will not cool quickly (the surface area is small), and this speed will decrease as it cools (the energy of thermal radiation decreases as the temperature decreases), but “absolute zero” for our “spherical” thermometer in a vacuum will be an asymptote - that is, its temperature will tend to absolute zero, but will never reach it.

In real space it will probably cool slowly (at a rate decreasing with time) until the absorbed cosmic radiation (from distant stars, etc.) balances the emitted thermal radiation. I assume it won't be very far from absolute zero.

UPD. Yes, and one more thing that I immediately forgot about: on a mercury thermometer the scale only goes up to 33-35 degrees Celsius, and when it cools down you need to “chicken out” because the mercury in it can easily be in an extended state, so it is possible that the readings will remain the same as they were before the launch, and perhaps when the mercury hardens, it will completely leave the tube with the scale and will be all in the tip flask - it will not show anything. In any case, such “readings” will have nothing to do with temperature.

I'll try to answer, maybe I'm missing something. So, the operating principle of mercury thermometers is based on the expansion of substances when they are heated. At the bottom of the thermometer there is always a reservoir with liquid, above it there is a narrow tube through which the liquid will rise (or fall) when the volume changes. As far as I understand, the question is what the thermometer will show in zero gravity conditions. So, if you shake it so that all the mercury ends up in the tank by inertia, then it will show exactly as many degrees as it really is. But we must remember that on most mercury thermometers the upper division is at up to 50 degrees Celsius, and our lower limit is limited by the melting point of mercury (something like -38). The question could also be aimed at what the thermometer will show in a vacuum. So it won't explode. There is already a vacuum in mercury thermometers. This is done so that the device responds to changes in temperature precisely at the point that comes into contact with the reservoir cone. Thermos and thermal mugs work on the same principle; they have double walls, and between the walls there is a vacuum that does not conduct heat. And the third version of the question: what will a thermometer show in a vacuum, which does not conduct heat. Here you need to take into account that the thermometer cone will heat up from the falling rays of stars. Well, or no stars. All three questions can be combined, but no matter how you look at it, in the short term the mercury in the thermometer will simply turn into solid state, because most of outer space has a temperature much lower than -38.

It will continue to show the temperature of the place from which it was “thrown out”. IN outer space vacuum is a very good heat insulator. And if this thermometer floats near some star (for example, in low-Earth orbit), it will even begin to heat up. And it will probably burst at some point.

Most likely it will be torn to pieces due to the oxygen contained in the body.

But if we imagine that we have an “indestructible” thermometer, then it all depends on where we throw it - if we throw it on the sunny side (let's say, within the first few planets solar system), then it will show quite high temperature about 107 degrees Celsius (this is the temperature of the “daytime” surface of the Moon) and the closer to the Sun, the higher. Otherwise, our indestructible device will show about minus 39 degrees (if such a scale is available) - this is the crystallization temperature of mercury.

There is a lot of research into various cosmic phenomena that affect temperature in space. Without going into details, the temperature varies, but is close to absolute zero (minus 273 degrees Celsius). But near the Sun the temperature is of course higher. For example, on the above Moon, “at night” it’s about minus 125 degrees.

but the method of manufacturing such thermometers fundamentally excludes the possibility of the presence of oxygen inside the mercury tube. And you can hammer it on the outer shell. In addition, it is worth remembering why we need to “shake off” a mercury thermometer before use - liquid mercury can be in a “stretched” state. So from simple cooling, if no one “resets” it, the “readings” will not change, but the temperature will not be shown either.

Answer

Comment

The purchased thermometer shows 1.5 degrees less (35.1 instead of 36.6), what can be done to change the calibration?
Igor, Omsk

Dear Igor, first of all, thank you for choosing our electronic thermometer. Unfortunately, you did not indicate the device model, so I cannot give you exact quotes from the instruction manual for your specific model. I'll take advantage classic instructions for electronic thermometer.

First, a few words about the operating principle of an electronic thermometer. Unlike the classic mercury, where the temperature is indicated due to an increase in the volume of mercury when heated, which by and large makes it unimportant how it is held, you can even cross it under the arm, it will not change anything, in electronic ones - the sensor is located at the end and only the heating of this part affects the temperature (the resistance of the conductor changes depending on the temperature) in the rest of the thermometer there are only wires. Thus, you need to look very carefully at how temperature is measured. The tip should be “stuck into the meat” i.e. firmly “stick” it into the armpit and press firmly with your hand. If the contact is not tight or the sensor is partially free, the temperature will be lower.

Further. The instructions state that " Sound signal is not a measurement completion signal. This means your temperature rises, but only slightly. We recommend holding the thermometer after the signal for a few more seconds." If we translate this into simple language, then after the thermometer beeps you need to take it out, look at the temperature, hold it (to be sure for another minute) then look at the indicators and remember the difference .And in the future add this difference to the measurement so as not to wait extra time.Usually the difference is 0.3-0.4 degrees.But the first time you need to check it.

Thus, an incorrect measurement technique and early removal of the thermometer can give an “error” of 1.5 degrees. But when correct use there won't be any problems.

If you doubt the accuracy of the thermometer reading, there is a fantastically simple test - pour a glass of warm water at about body temperature. Or a hot bath. Place the mercury and the tip of an electronic thermometer there. The data will be the same after 3 minutes. This will give you the opportunity to judge how well the thermometer is working. If this test shows that there are problems with the thermometer, contact service center. I'm sure they can help you.

This all applies to the classic electronic thermometer. If you have an infrared thermometer, then write. I will tell you how to properly maintain and measure with this device. I am sure that all problems can be solved.

The history of the creation of the thermometer begins many years ago. People have always wanted to have a device that allows them to measure the amount of heating or cooling of a certain object. This opportunity arose in 1592, when Galileo designed the first instrument that made it possible to determine temperature changes. This device, consisting of glass ball and the tube soldered to it was called a thermoscope. The end of the tube was placed in a vessel with water, and the ball was heated. When heating stopped, the pressure inside the ball dropped, and water rose through the tube under the influence of atmospheric pressure. As the temperature increased, the reverse process occurred and the water level in the tube decreased. The device did not have a scale, and exact values It was impossible to determine the temperature from it. Subsequently, Florentine scientists eliminated this shortcoming, as a result of which the measurements became more accurate. This is how the prototype of the first thermometer was created.

At the beginning of the next century, the famous Florentine scientist, a student of Galileo, Evangelista Torricelli invented an alcohol thermometer. As we all know well, the ball in it is located under a glass tube, and alcohol is used instead of water. The readings of this device do not depend on atmospheric pressure.

Invention of the first mercury thermometer D.G. Fahrenheit dates back to 1714. He took 32 degrees as the lowest point of his shawl - which corresponded to the freezing temperature saline solution, and for the upper one - 2120 - the boiling point of water. The Fahrenheit scale is still used in the United States today.

In 1730, French scientist R.A. Reaumur proposed a scale in which the extreme points were the boiling and freezing temperatures of water, and the freezing point of water was taken as 0 degrees on the Reaumur scale, and the boiling point as 80 degrees. Currently, the Reaumur scale is practically not used.

28 years later, the Swedish researcher A. Celsius developed his own scale, where the boiling and freezing temperatures of water were taken as the extreme points, as in the Reaumur scale, but the interval between them was divided not by 80, but by 100 degrees, and initially the graduation was from the top down, that is, the boiling point of water was taken as zero, and the freezing point of water as one hundred degrees. The inconvenience of such a division soon became obvious, and subsequently Stremmer and Linnaeus swapped the extreme points of the scale, giving it the appearance we are familiar with.

In the middle of the 19th century, the British scientist William Thomson, known as Lord Kelvin, proposed a temperature scale whose lowest point was -273.15 0C - absolute zero, at this value there is no movement of molecules.

This is how we can briefly describe the history of the creation of the thermometer and temperature scales. Currently, the most widely used thermometers are the Celsius scale, the Fahrenheit scale is still used in the United States, and the Kelvin scale is the most popular in science.

Today, there are many designs of thermometers and temperature measuring devices, based on various physical properties and widely used in everyday life, science and production.

Probably, each of us has encountered a situation where measuring an elevated temperature due to an illness gives rather ambiguous results: either the thermometer readings are too high, while the state of health does not seem so bad, or, on the contrary, we suspect the thermometer of downplaying the seriousness of the situation .

Things can get even more confusing when you measure temperature with more than one type of thermometer: mercury thermometer, electronic thermometer, or infrared thermometer (also called an electronic non-contact thermometer).

In the instructions supplied with the thermometers, you can find information that the error of mercury and electronic thermometers is 0.1 °C, and for infrared thermometers it is a little more - 0.2-0.3 °C. However, you can also come across reviews from people who write: the error of an electronic thermometer sometimes reaches 0.5 °C. The science department decided to figure out whether a mercury thermometer, the principle of operation of which is based on the thermal expansion of mercury, is really the most accurate, and also to understand how to properly use electronic instruments for measuring temperature by contacting an expert and conducting its own experiment.

Expert

Vladimir Sedykh answered the questions, commercial director of one of the companies producing thermometers .

— Is it possible to say that mercury thermometers are more accurate than electronic ones?

- No. Electronic thermometers are no different in accuracy from mercury thermometers: the measurement error of both thermometers is 0.1°C. The problem with electronic thermometers is that to effectively measure temperature, the thermometer must fit very tightly to the surface of the body, so it is advisable to use it in the oral or anal openings.

Almost all electronic thermometers are designed to measure human body temperature by oral or anal methods, but in Russia this method of measurement is unpopular.

When using electronic thermometers, it is very important to observe right time measurements. The instructions often write: measurement time - 10 seconds. But you need to hold it for at least 5 minutes. Usually, when the thermometer takes the first reading, it makes a characteristic squeak. After this squeak, it is better to hold it for a couple more minutes.

- But if electronic device detects temperature almost instantly, why keep it for several minutes?

— Mercury and electronic thermometers are removed different temperatures: mercury shows maximum temperature for a certain period of time. (That is, if you hold it for five minutes, it will show the maximum temperature you had during those five minutes.) An electronic thermometer takes the temperature in a matter of seconds, and you need to hold it for several minutes so that it averages the resulting value. It is worth remembering that the body temperature of any person can fluctuate by quite a lot even within a minute. large values- up to 1°C.

— Is there anything else that can interfere with the accuracy of data obtained using electronics?

— The operation of electronic thermometers is affected by another factor - the voltage drop in the batteries. As a rule, all batteries last on average about two years; if you do not change the battery on time, the thermometer will begin to “lie.” Like almost everyone measuring instruments(for example, tonometers), thermometers have a calibration interval, usually one to two years. But a glass thermometer is not checked during its entire service life! Therefore, all electronic thermometers must be tested at least once a year, for some products - once every two years. This must be indicated in technical passport products. Manufacturers usually write: the warranty on the thermometer is for so many years. But if you read the instructions carefully, it will say:

In order for this guarantee to be maintained and for the device to show the exact temperature during the warranty period, it must be regularly brought either to the service center of the manufacturer, or simply to the metrological service.

The cost of testing, or rather verification (metrological term), of one electronic thermometer can reach up to 1 thousand rubles.

— What advantages does a glass thermometer have over an electronic one?

- Unlike an electronic thermometer, the service life of a glass thermometer is not limited - of course, in the absence mechanical damage. If you use it carefully, it will serve, one might say, forever. The accuracy of the thermometer does not change over the years, it is sealed, waterproof, anti-allergenic, and does not require battery replacement. The only disadvantage of an old mercury thermometer is mercury, or rather, mercury vapor. In Europe, these are prohibited, and glass thermometers without mercury have been used there for a long time. More recently, these appeared in Russia. In glass thermometers of a new type

Instead of mercury, a non-toxic metal alloy consisting of gallium, indium and tin is used. This thermometer is environmentally friendly, safe, and non-toxic.

— What can you say about electronic non-contact thermometers - infrared?

— With infrared thermometers, an accuracy of ±0.1 °C cannot be achieved because the beam measuring the temperature passes through air currents: air conditioning, heater, your forehead is wet - all this affects the measurement result. Of course, I cannot say one hundred percent, but I have seen a huge number of infrared thermometers, and I have not seen one with an error of ± 0.1 °C. Best indicator is ±0.2 °C. Infrared thermometers are convenient to use, for example, in the sanitary area of ​​an airport for quick, non-contact temperature measurement.

— What thermometer do you recommend using at home?

— In general, it is recommended to have at home one electronic or infrared thermometer for quick measurements and one mercury thermometer, or better yet a mercury-free glass one, to monitor the temperature over time if a person is already sick. Although, of course, it’s best not to get sick, which is what I wish for you!

Experiment

During the experiment, correspondents from the science department recruited colleagues from the technology department and used three thermometers: glass mercury, electronic and infrared. Five people took part in the experiment, each of whom measured their temperature five times: the first time - with a mercury thermometer, the second - electronically, but in the “wrong” way we are used to, in the armpit (it is worth noting that this method was indicated in the instructions for the thermometer as having the right to life), the third - with an electronic thermometer, placing it, according to the instructions, under the tongue, the fourth - with an infrared thermometer. The last time we measured the temperature again with the same thermometer, but before that we carefully wiped its sensor. Our results can be seen in the table below.

Zero on the Faraday scale was equal to modern 32 degrees, and the temperature of the human body was equal to 96 degrees. In 1742, the physicist Celsius made the temperature of melting ice and boiling water the reference points, although initially zero on the scale corresponded to the boiling temperature of water, but then it became the same.

Liquid thermometers operate on the principle of changing the initial volume of liquid poured into the thermometer when changing ambient temperature. Most often, alcohol or mercury is poured into the thermometer flask. The advantages of a mercury thermometer are high accuracy of temperature measurement, long service life, however, the temperature level takes a long time to set, mercury in a thermometer is a dangerous material, so using a mercury thermometer must be done as carefully as possible.
Optical thermometers record temperature based on the level of glow, spectrum and other indicators and are most often used in scientific research.

Mechanical thermometers operate on the principle of liquid thermometers, only the sensor is a spiral or metal tape.
Electrical - they work on the principle of changing the resistance level of the conductor when changing external temperature. Those electric thermometers that have a large range are based on thermocouples - when different metals interact, a contact potential difference arises, which depends on temperature. Electric thermometers have built-in additional functions memory, backlight, they are safe and quickly show the result, but they can give a small error, as a result of which the temperature must be measured several times.

An infrared thermometer measures temperature without direct interaction with a person or object, and is characterized by measurement accuracy and safety, as well as high speed actions - half a second. They are hygienic, work quickly (within 2-5 seconds) and help measure the temperature of children.

Video on the topic

It is known that hotter bodies conduct worse electricity than chilled ones. The reason for this is the so-called thermal resistance metals

What is thermal resistance

Thermal resistance is the resistance of a conductor (section of a circuit) due to the thermal movement of charge carriers. By charges here we must understand the electrons and ions contained in the substance. From the name it is clear that we are talking about the electrical phenomenon of resistance.

The essence of thermal resistance

The physical essence of thermal resistance lies in the dependence of electron mobility on the temperature of the substance (conductor). Let's figure out where this pattern comes from.

Conductivity in metals is provided by free electrons, which, under the influence of electric field acquire directional movement along the electric field lines. Thus, it is reasonable to ask: what can impede the movement of electrons? The metal contains an ionic crystal lattice, which, of course, slows down the transfer of charges from one end of the conductor to the other. It should be noted here that the ions crystal lattice are in oscillatory motion, therefore, they occupy a space limited not by their size, but by the amplitude of their oscillations. Now you need to think about increasing the temperature of the metal. The fact is that the essence of temperature is precisely the vibrations of the ions of the crystal lattice, as well as the thermal movement of free electrons. Thus, by increasing the temperature, we increase the amplitude of vibrations of the ions of the crystal lattice, and therefore create a greater obstacle to the directional movement of electrons. As a result, the resistance of the conductor increases.

On the other hand, as the temperature of the conductor increases, the thermal movement of electrons also increases. This means that their movement is becoming more chaotic than directed. The higher the temperature of the metal, the more degrees of freedom manifest themselves, the direction of which does not coincide with the direction of the electric field. This also causes a greater number of collisions of free electrons with ions of the crystal lattice. Thus, the thermal resistance of a conductor is determined not only by the thermal motion of free electrons, but also by the thermal vibrational motion of the ions of the crystal lattice, which becomes more and more noticeable as the temperature of the metal increases.

From all that has been said, we can conclude that the best conductors are “cold”. It is for this reason that superconductors, whose resistance is zero, contain extremely low temperatures, calculated in Kelvin units.

Video on the topic

Tip 3: Temperature sensor: operating principle and scope of application

Current equipment, automation and automotive industry are unlikely to do without any kind of controllers. This type of device also includes temperature sensors, the scope of which is unlimited.

Device

1. Thermal resistance sensor. Such devices operate on the principle of changing the electrical resistance of a conductor when temperature fluctuations occur. These sensors are easy to use, they are very reliable, sensitive, and more accurate.

2. Semiconductor thermal sensors are designed on the principle of responding to the transformation of the characteristics of a (p-n) junction under the influence of temperature. The series of such sensors is very simple in its design and has an excellent price-durability ratio.

3. Thermoelectric sensors, or thermocouples as they are also called. This type of sensor works on the effect of the temperature difference between a pair of conductors that are in different environments. Due to this, a pulse appears in the closed circuit of this pair of conductors; the sensors signal a change in temperature relative to each other. These devices do not provide the same accuracy as their counterparts described above, and are structurally more cumbersome.

4. Pyrometers. These are non-contact type sensors; they record the temperature near an object. This type of device has the big advantage that it can operate at a distance from the mechanism in which temperature readings need to be recorded.

5. Acoustic sensors. The operating principle is based on the change in the speed of sound in the atmosphere when the temperature of the environment in which the sensor is located changes. Such devices are used in environments where it is impossible to use contact sensors temperature.

6. Piezoelectric sensors. The meaning of the device is as follows: on quartz base, which the sensor itself consists of, delivers a certain series of pulses, thus, with a change in temperature, this material has a different expansion frequency.

Application