Infrared light – a workshop on invisibly warm radiation. Beneficial and harmful properties of infrared radiation on humans Infrared radiation application briefly

Infrared radiation sources

A powerful source of infrared radiation is the Sun, about 50% of which lies in the infrared region. A significant proportion (from 70 to 80%) of the radiation energy of incandescent lamps with tungsten filament comes from infrared radiation.

When photographing in the dark and in some night observation devices, the backlight lamps are equipped with an infrared filter that transmits only infrared radiation. A powerful source of infrared radiation is a carbon electric arc with a temperature of ~ 3900 K, the radiation of which is close to the radiation of a black body, as well as various gas-discharge lamps (pulsed and continuous burning). For radiation heating of rooms, spirals made of nichrome wire are used, heated to a temperature of ~ 950 K. For better concentration of infrared radiation, such heaters are equipped with reflectors. In scientific research, for example, when obtaining infrared absorption spectra in different regions of the spectrum, special sources of infrared radiation are used: tungsten strip lamps, Nernst pin, globar, high-pressure mercury lamps, etc.

The radiation of some optical quantum generators - lasers also lies in the infrared region of the spectrum; for example, the radiation from a neodymium glass laser has a wavelength of 1.06 µm, a laser on a mixture of neon and helium - 1.15 µm and 3.39 µm, a carbon dioxide laser - 10.6 µm, a semiconductor laser on InSb - 5 µm and etc. Infrared radiation receivers are based on the conversion of infrared radiation energy into other types of energy that can be measured by conventional methods.

There are thermal and photoelectric receivers of infrared radiation. In the first, absorbed infrared radiation causes an increase in the temperature of the thermosensitive element of the receiver, which is recorded. In photoelectric receivers, absorbed infrared radiation leads to the appearance or change of electric current or voltage. Photoelectric receivers, unlike thermal ones, are selective receivers, i.e., sensitive only in a certain region of the spectrum. Special photographic films and plates - infraplates - are also sensitive to infrared radiation (up to l = 1.2 microns), and therefore photographs can be taken in infrared radiation.

Applications of Infrared Radiation

Infrared radiation is widely used in scientific research, in solving a large number of practical problems, in military affairs, etc. The study of emission and absorption spectra in the infrared region is used in studying the structure of the electron shell of atoms, to determine the structure of molecules, as well as for the qualitative and quantitative analysis of mixtures of substances complex molecular composition, such as motor fuel. Due to the difference in the scattering, reflection and transmission coefficients of bodies in visible and infrared radiation, photography obtained in infrared radiation has a number of features compared to conventional photography. For example, infrared images often reveal details that are not visible in a regular photograph.

In industry, infrared radiation is used for drying and heating materials and products when they are irradiated, as well as for detecting hidden defects in products.

Based on photocathodes sensitive to infrared radiation (for l< 1,3 мкм), созданы специальные приборы - электроннооптические преобразователи, в которых не видимое глазом инфракрасное изображение объекта на фотокатоде преобразуется в видимое. На этом принципе построены различные приборы ночного видения (бинокли, прицелы и др.), позволяющие при облучении наблюдаемых объектов инфракрасным излучением от специальных источников вести наблюдение или прицеливание в полной темноте. Создание высокочувствительных приёмников Инфракрасного излучения позволило построить специальные приборы - теплопеленгаторы для обнаружения и пеленгации объектов, температура которых выше температуры окружающего фона (нагретые трубы кораблей, двигатели самолётов, выхлопные трубы танков и др.), по их собственному тепловому Инфракрасному излучению. На принципе использования теплового излучения цели созданы также системы самонаведения на цель снарядов и ракет. Специальная оптическая система и приёмник инфракрасного излучения, расположенные в головной части ракеты, принимают инфракрасное излучение от цели, температура которой выше температуры окружающей среды (например, собственное инфракрасное излучение самолётов, кораблей, заводов, тепловых электростанций), а автоматическое следящее устройство, связанное с рулями, направляет ракету точно в цель. Инфракрасные локаторы и дальномеры позволяют обнаруживать в темноте любые объекты и измерять расстояния до них.

Optical quantum generators emitting in the infrared region are also used for terrestrial and space communications.

Infrared (IR) rays are electromagnetic waves. The human eye is not able to perceive this radiation, but a person perceives it as thermal energy and feels it throughout the skin. We are constantly surrounded by sources of infrared radiation, which differ in intensity and wavelength.

Should we be wary of infrared rays, do they bring harm or benefit to humans, and what is their effect?

What is IR radiation and its sources?

As is known, the spectrum of solar radiation, perceived by the human eye as visible color, lies between violet waves (the shortest - 0.38 microns) and red (the longest - 0.76 microns). In addition to these waves, there are electromagnetic waves that are inaccessible to the human eye - ultraviolet and infrared. "Ultra" means that they are below or in other words less violet radiation. “Infra”, respectively, is higher or more red radiation.

That is, IR radiation is electromagnetic waves lying beyond the red color range, the length of which is longer than that of visible red radiation. While studying electromagnetic radiation, German astronomer William Herschel discovered invisible waves that caused the temperature of the thermometer to rise, and called them infrared thermal radiation.

The most powerful natural source of thermal radiation is the Sun. Of all the rays emitted by the star, 58% are infrared. Artificial sources are all electric heating devices that convert electricity into heat, as well as any objects whose temperature is above absolute zero - 273 ° C.

Properties of infrared radiation

IR radiation has the same nature and properties as ordinary light, only a longer wavelength. Light waves visible to the eye, reaching objects, are reflected and refracted in a certain way, and a person sees the reflection of the object in a wide range of colors. And infrared rays, upon reaching an object, are absorbed by it, releasing energy and heating the object. We do not see infrared radiation, but we feel it as heat.

In other words, if the Sun did not emit a wide spectrum of long-wave infrared rays, a person would only see sunlight, but not feel its heat.

It is difficult to imagine life on Earth without solar heat.

Some of it is absorbed by the atmosphere, and the waves reaching us are divided into:

Short - the length lies in the range of 0.74 microns - 2.5 microns, and they are emitted by objects heated to a temperature of more than 800 ° C;

Medium – from 2.5 microns to 50 microns, heating temperature from 300 to 600°C;

Long – the widest range from 50 microns to 2000 microns (2 mm), t up to 300°C.

The properties of infrared radiation, its benefits and harm to the human body, are determined by the source of radiation - the higher the temperature of the emitter, the more intense the waves and the deeper their penetrating ability, the degree of impact on any living organisms. Studies conducted on cellular material of plants and animals have discovered a number of useful properties of infrared rays, which have found wide application in medicine.

The benefits of infrared radiation for humans, application in medicine

Medical research has proven that long-range infrared rays are not only safe for humans, but also very useful. They activate blood flow and improve metabolic processes, suppress the development of bacteria and promote rapid healing of wounds after surgical interventions. They promote the development of immunity against toxic chemicals and gamma radiation, stimulate the elimination of toxins and waste through sweat and urine and lower cholesterol.

Particularly effective are rays with a length of 9.6 microns, which promote regeneration (restoration) and healing of organs and systems of the human body.

From time immemorial, folk medicine has used treatment with heated clay, sand or salt - these are vivid examples of the beneficial effects of thermal infrared rays on humans.

Modern medicine has learned to use beneficial properties to treat a number of diseases:

Using infrared radiation, you can treat bone fractures, pathological changes in joints, and relieve muscle pain;

IR rays have a positive effect in the treatment of paralyzed patients;

Quickly heal wounds (postoperative and other), relieve pain;

By stimulating blood circulation, they help normalize blood pressure;

Improves blood circulation in the brain and memory;

Remove heavy metal salts from the body;

They have a pronounced antimicrobial, anti-inflammatory and antifungal effect;

Strengthen the immune system.

Bronchial asthma, pneumonia, osteochondrosis, arthritis, urolithiasis, bedsores, ulcers, radiculitis, frostbite, diseases of the digestive system - this is not a complete list of pathologies for the treatment of which the positive effects of infrared radiation are used.

Heating residential premises using infrared radiation devices promotes air ionization, fights allergies, destroys bacteria, mold fungi, and improves the condition of the skin by activating blood circulation. When purchasing a heater, it is imperative to choose long-wave devices.

Other Applications

The property of objects to emit heat waves has found application in various areas of human activity. For example, with the help of special thermographic cameras capable of capturing thermal radiation, you can see and recognize any objects in absolute darkness. Thermographic cameras are widely used in military and industrial applications to detect invisible objects.

In meteorology and astrology, infrared rays are used to determine distances to objects, clouds, water surface temperature, etc. Infrared telescopes make it possible to study space objects that are inaccessible to vision through conventional instruments.

Science does not stand still and the number of IR devices and areas of their application is constantly growing.

Harm

A person, like any body, emits medium and long infrared waves, which range from 2.5 microns to 20-25 microns in length, therefore waves of this length are completely safe for humans. Short waves are able to penetrate deeply into human tissue, causing heating of internal organs.

Short-wave infrared radiation is not only harmful, but also very dangerous for humans, especially for the visual organs.

Solar heatstroke, provoked by short waves, occurs when the brain heats up by only 1C. Its symptoms are:

Severe dizziness;

Nausea;

Increased heart rate;

Loss of consciousness.

Metallurgists and steelworkers, constantly exposed to the thermal effects of short infrared rays, are more likely than others to suffer from diseases of the cardiovascular system, have a weakened immune system, and are more often exposed to colds.

To avoid the harmful effects of infrared radiation, it is necessary to take protective measures and limit the time spent under dangerous rays. But the benefits of thermal solar radiation for life on our planet are undeniable!

In 1800, scientist William Herschel announced his discovery at a meeting of the Royal Society of London. He measured temperatures outside the spectrum and discovered invisible rays with great heating power. He carried out the experiment using telescope filters. He noticed that they absorb light and heat from the sun's rays to varying degrees.

After 30 years, the existence of invisible rays located beyond the red part of the visible solar spectrum was indisputably proven. The French Becquerel called this radiation infrared.

Properties of IR radiation

The spectrum of infrared radiation consists of individual lines and bands. But it can also be continuous. It all depends on the source of the IR rays. In other words, what matters is the kinetic energy or temperature of an atom or molecule. Any element of the periodic table has different characteristics at different temperatures.

For example, the infrared spectra of excited atoms, due to the relative state of rest of the nucleus bundle, will have strictly line IR spectra. And excited molecules are striped and randomly located. Everything depends not only on the mechanism of superposition of the own linear spectra of each atom. But also from the interaction of these atoms with each other.

As the temperature rises, the spectral characteristics of the body change. Thus, heated solids and liquids emit a continuous infrared spectrum. At temperatures below 300°C, the radiation of a heated solid is entirely in the infrared region. Both the study of IR waves and the application of their most important properties depend on the temperature range.

The main properties of IR rays are absorption and further heating of bodies. The principle of heat transfer by infrared heaters differs from the principles of convection or conduction. Being in a flow of hot gases, an object loses some amount of heat as long as its temperature is lower than the temperature of the heated gas.

And vice versa: if infrared emitters irradiate an object, this does not mean that its surface absorbs this radiation. It can also reflect, absorb or transmit rays without loss. Almost always, the irradiated object absorbs part of this radiation, reflects part and transmits part.

Not all luminous objects or heated bodies emit infrared waves. For example, fluorescent lamps or the flame of a gas stove do not have such radiation. The operating principle of fluorescent lamps is based on glow (photoluminescence). Its spectrum is closest to the spectrum of daylight, white light. Therefore, there is almost no IR radiation in it. And the highest intensity of radiation from a gas stove flame occurs at the blue wavelength. The IR radiation of the listed heated bodies is very weak.

There are also substances that are transparent to visible light, but are not capable of transmitting infrared rays. For example, a layer of water several centimeters thick will not transmit infrared radiation with a wavelength greater than 1 micron. In this case, a person can distinguish objects located at the bottom with the naked eye.

Theory of infrared radiation

All the variety ofteachings emanating from the Sun have a single nature -these are electromagnetic waves. The diversity in their properties is caused by differences in wavelength. The visible part of the solar radiation spectrum begins with the shortest waves - violet waves (0.38 microns) and ends with the longest waves (0.76 microns), which the human eye perceives as red.

The German scientist William Herschel in 1800 discovered certain invisible rays beyond the red part of the spectrum, causing a significant increase in the temperature of the thermometer he used for research. This radiation was called infrared.

What is the effect of infrared radiation on the human body? Let's find out.

What is infrared radiation

Radiation adjacent to the red part of the visible spectrum, not perceived by our organs of vision, but having the ability to heat illuminated surfaces, was called infrared. The prefix "infra" means "more". In our case, these are electromagnetic rays with a wavelength greater than that of visible red light.

What is the source of infrared radiation

Its natural source is the Sun. The range of infrared rays is quite wide. These are waves with a length from 7 to 14 micrometers (µm). Partial absorption and scattering of infrared rays occurs in the Earth's atmosphere.

The scale of infrared solar radiation is evidenced by the fact that it accounts for 58% of the entire spectrum of electromagnetic waves emanating from our star.

This fairly wide range of IR rays is divided into three parts:

long waves emitted by a heater with a temperature of 35 to 300 °C;

medium - from 300 to 700 °C;

short - more than 700 °C.

All of them are emitted by excited atoms (i.e., those with excess energy), as well as ions of the substance. All bodies are a source of IR radiation if their temperature is above absolute zero (minus 273 °C).

So, depending on the temperature of the emitter, IR rays of different wavelengths, intensities and penetrating abilities are formed. And this determines how infrared radiation affects a living organism.

The benefits and harms of IR radiation for human health

You can answer the question - is infrared radiation harmful to humans, armed with some information.

Long-wave infrared rays hitting the skin affect nerve receptors, causing a feeling of warmth. Therefore, infrared radiation is also called thermal radiation.

More than 90% of this radiation is absorbed by moisture contained in the upper layers of the skin. It only causes an increase in the temperature of the skin. Medical research has shown that long-wave radiation is not only safe for humans, but also improves immunity and triggers the mechanism of regeneration and healing of many organs and systems. IR rays with a wavelength of 9.6 microns are especially effective in this regard. These circumstances determine the use of infrared radiation in medicine.

A completely different mechanism of action of infrared rays on the human body, which belongs to the short-wave part of the spectrum. They are able to penetrate to a depth of several centimeters, causing heating of internal organs.

At the site of irradiation, due to dilation of the capillaries, redness of the skin may appear, including the formation of blisters. Short IR rays are especially dangerous for the organs of vision. They can provoke the formation of cataracts, disturbances in water-salt balance, and the appearance of seizures.

The cause of the well-known thermal shock effect is short-wave infrared radiation. An increase in brain temperature of 1 °C already causes its symptoms:

dizziness;

nausea;

increased heart rate;

darkening of the eyes.

Overheating by 2 °C can trigger the development of meningitis.

Now let's understand the concept of intensity of electromagnetic radiation. This factor depends on the distance to the heat source and its temperature. Low-intensity long-wave thermal radiation plays an important role for the development of life on the planet. The human body needs constant replenishment of these wavelengths.

Thus, the harm and benefits of infrared radiation are determined by the wavelength and exposure time.

How to avoid harmful effects of IR rays

Heaters are sources of IR radiation.

Since we have decided that short-wave infrared radiation has a negative effect on the human body, let's find out where this danger may lie in wait for us. First of all, these are bodies with temperature, exceeding 100 °C. These may include the following. Industrial sources of radiant energy (steel melting, electric arc furnaces, etc.) Reducing the risk of their exposure is achieved by special protective clothing, heat shields, the use of newer technologies, as well as therapeutic and preventive measures for operating personnel.

Heaters. The most reliable and proven of them is the Russian stove. The warmth it emits is not only extremely pleasant, but also healing. Unfortunately, this detail of everyday life has almost completely sunk into oblivion. It was replaced by all possible electric heaters, water infrared panels, etc.. Those whose heat-generating surface is protected by heat-insulating material or whose radiation surface temperature is below 100°C , emit soft long-wave radiation. It has a beneficial effect on the body. Heaters with a higher radiation surface 100 °C emit hard, short-wave radiation, which can lead to the negative consequences described above. In the technical data sheet of the heater, the manufacturer is obliged to indicate the nature of the radiation of this device.

Shortwave heater.

If you become the owner of a short-wave heater, follow the rule - the closer the heater is, the shorter its exposure time should be!!!

At all times, infrared radiation has surrounded man. Before the advent of technological progress, the rays of the sun had an impact on the human body, and with the advent of household appliances, infrared radiation also has an effect at home. Therapeutic heating of body tissues is successfully used in medicine for the physiotherapeutic treatment of various pathologies.

The properties of infrared radiation have long been studied by physicists and are aimed at obtaining maximum benefits and benefits for humans. All parameters of harmful effects were taken into account and methods of protection were recommended to preserve human health.

Infrared rays: what are they?

Invisible electromagnetic radiation that provides a strong thermal effect is called infrared. The rays range in length from 0.74 to 2000 µm, which is between microwave radio emission and visible red rays, which are the longest in the sun's spectrum.

Back in 1800, British astronomer William Herschel discovered electromagnetic radiation. This happened while studying the rays of the sun: the scientist noticed a significant heating of the instruments and was able to differentiate invisible radiation.

Infrared radiation has a second name - “thermal”. Heat emanates from objects that can maintain temperature. Short infrared waves heat more strongly, and if the heat is felt weak, it means that long-range waves are emanating from the surface. There are three types of wavelengths of infrared radiation:

short or short up to 2.5 microns;
average no more than 50 microns;
long or distant 50–2000 µm.

Any body that has been previously heated emits infrared rays, releasing thermal energy. The most famous natural source of heat is the sun, and artificial ones include electric lamps, household appliances, and radiators, the operation of which generates heat.

Where is infrared radiation used?

Each new discovery finds its application, with the greatest benefit for humanity. The discovery of infrared rays helped solve many problems in various fields from medicine to industrial scale.

The most famous areas where the properties of invisible rays are used:

With the help of special devices, thermal imagers, you can detect an object at a remote distance using the properties of infrared radiation. Any object capable of maintaining temperature on its surface, thereby emitting infrared rays. A thermographic camera detects heat rays and creates an accurate image of the object being detected. This property can be used in industry and military practice.
To carry out the tracking procedure in military practice, devices with sensors that can detect a target that emits heat are used. In addition, what exactly is in the immediate environment is transmitted in order to correctly calculate not only the trajectory, but also the force of the impact, most often a missile.
Active heat transfer together with rays is used in domestic conditions, using beneficial properties for heating a room in the cold season. Radiators are made of metal, which is capable of transmitting the greatest amount of thermal energy. The same effect applies to heaters. Some household appliances: televisions, vacuum cleaners, stoves, irons have the same properties.
In industry, the process of welding plastic products and annealing is carried out using infrared radiation.
Infrared irradiation is used in medical practice to treat certain pathologies with heat, as well as to disinfect indoor air using quartz lamps.
Compiling weather maps is impossible without special instruments with thermal detection sensors that easily determine the movement of warm and cold air.
For astronomical research, special telescopes are made that are sensitive to infrared rays, which are capable of detecting space objects with different temperatures on the surface.
In the food industry for heat treatment of cereals.
To check banknotes, devices with infrared radiation are used, by the light of which counterfeit banknotes can be recognized.

The effect of infrared radiation on the human body is ambiguous. Different wavelengths can trigger unpredictable reactions. You need to be especially careful about the heat of the sun, which can cause harm and become a provoking factor for the launch of negative pathological processes in cells.

Long-wavelength rays hit the skin and activate heat receptors, imparting pleasant warmth to them. It is this frequency range that is actively used for therapeutic effects in medicine. Most of the heat is absorbed by the skin, falling on its surface. Low impact guarantees pleasant heating of the skin surface without affecting the internal organs.

Waves with a wavelength of 9.6 microns promote renewal of the epidermis, strengthen the immune system, and heal the body. Physiotherapy is based on the use of long infrared waves, triggering the following processes:

blood circulation improves when smooth muscles relax after transmitting information to the hypothalamus when affecting the surface layer of the skin;
blood pressure normalizes after vasodilation;
the body's cells are more supplied with nutrients and oxygen, which improves the general condition;
biochemical reactions proceed faster, which affects the metabolic process;
immunity improves and the body's resistance to pathogenic microorganisms increases;
accelerating metabolism helps remove toxic substances and reduce slagging.

Pathological influence

Waves with a short wavelength have the opposite effect. The harm of infrared radiation is due to the intense thermal effect caused by short rays. A strong thermal effect spreads deep into the body, causing heating of the internal organs. Overheating of tissues leads to dehydration and a significant increase in body temperature.

The skin at the site of contact with short-length infrared rays turns red and receives a thermal burn, sometimes of the second degree of severity with the appearance of blisters with cloudy contents. The capillaries at the site of the lesion expand and burst, leading to small hemorrhages.

Cells lose moisture, the body becomes weakened and susceptible to infections of various types. If infrared radiation enters the eyes, this fact has a destructive effect on vision. The mucous membrane of the eye becomes dry, the retina is negatively affected. The lens loses its elasticity and transparency, which is one of the symptoms of cataracts.

Excessive heat exposure causes an increase in inflammatory processes, if any, and also serves as a fertile ground for the occurrence of inflammation. Doctors say that exceeding the temperature by a couple of degrees can provoke infection with meningitis.

A general increase in body temperature leads to heat stroke, which, if help is not provided, can lead to irreversible consequences. Main signs of heat stroke:

general weakness;
Strong headache;
blurred vision;
nausea;
increased heart rate;
the appearance of cold sweat on the back;
short-term loss of consciousness.

A serious complication associated with impaired thermoregulation occurs if the frequency of exposure to infrared radiation continues for a long time. If a person is not provided with timely assistance, brain cells are modified, and the activity of the circulatory system is inhibited.

List of activities in the first minutes after the onset of alarming symptoms:

Remove the source of infrared radiation from the victim: move the person to the shade or to a place away from the source of harmful heat.
Unbutton or remove any clothing that may interfere with deep, free breathing.
Open the window to allow fresh air to flow freely.
Wipe with cool water or wrap in a wet sheet.
Apply cold to the places where large arteries are located (temporal, groin, forehead, armpits).
If the person is conscious, he should be given cool, clean water to drink; this measure will lower the body temperature.
In case of loss of consciousness, a resuscitation complex should be performed, consisting of artificial respiration and chest compressions.
Call an ambulance to receive qualified medical care.

Indications

For therapeutic purposes, the use of long thermal waves is widely used in medical practice. The list of diseases is quite long:

high blood pressure;
pain syndrome;
will help you lose extra pounds;
diseases of the stomach and duodenum;
depressive states;
respiratory diseases;
skin pathologies;
rhinitis, uncomplicated otitis.

Contraindications to the use of infrared radiation

The benefits of infrared radiation are valuable for humans in the absence of pathologies or individual symptoms in which exposure to infrared rays is unacceptable:

systemic blood diseases, tendency to frequent bleeding;
acute and chronic inflammatory diseases;
the presence of purulent infection in the body;
malignant neoplasms;
heart failure in the stage of decompensation;
pregnancy;
epilepsy and other severe neurological disorders;
children up to three years of age.

Protective measures against harmful rays

Those at risk of receiving short-wave infrared radiation include those who like to spend long periods of time under the scorching sun and workers in workshops where the properties of heat rays are used. To protect yourself, you need to follow simple recommendations:

Those who like a beautiful tan should reduce their time in the sun and lubricate exposed skin with a protective cream before going outside.
If there is a source of intense heat nearby, reduce the heat intensity.
When working in workshops with high temperatures, workers must be equipped with personal protective equipment: special clothing, hats.
The time spent in rooms with high temperatures must be strictly regulated.
When carrying out procedures, wear protective glasses to maintain eye health.
Install only high-quality household appliances in the rooms.

Various types of radiation surround a person outdoors and indoors. Being aware of possible negative consequences will help you stay healthy in the future. The value of infrared radiation is undeniable for improving human life, but there is also a pathological effect that needs to be eliminated by following simple recommendations.