Infrared, translated as infrared radiation, is actually an electromagnetic wave. This infrared radiation cannot be seen by the human eye. But its radiation waves can be felt as heat. Simply put, it’s a heat wave. It’s not exactly true. But for those who don’t have a physics background, it’s easy to understand because infrared radiation is compared to heat waves.
Everything in the universe emits infrared radiation. For humans on Earth, there are two main objects that emit infrared radiation. That is the sun and fire.
Infrared radiation is electromagnetic waves, so let’s take a look at what electromagnetic waves are.
Electromagnetic Spectrum
Everything in the universe is made up of atoms. (You can dissect the atom again, but you don’t need to know that much to understand electromagnetic waves.) These atoms have the ability to absorb and release energy. When these atoms give off energy, they come out as electromagnetic waves.
All stars and galaxies emit electromagnetic waves. These resulting waves are classified based on their wavelength. From the shortest wavelength to the longest wavelength:
- gamma-rays
- X-Rays
- Ultraviolet light
- visible light
- infrared radiation
- Microwaves
- Radio waves
In this electromagnetic spectrum, the wavelength of infrared radiation is longer than that of red. The longer the wavelength, the lower the frequency. Because of the low frequency, the energy of this infrared radiation is lower than the energy of light (I will write an article about this later). It has more energy than red, so it is named infrared.
Infrared waves were first discovered in 1800 by British astronomer William Herschel. It was discovered unexpectedly during a research experiment to measure the temperature difference between one color of the rainbow spectrum of light. To measure the color of the rainbow spectrum, a row of mercury thermometers was placed at each temperature along the path of each spectrum. At this time, I noticed a significant difference in temperature between blue and red. (Between blue and red, green, yellow, and orange are still different.) But one thing I didn’t expect was that the temperature in the small field next to Red rose significantly. (This is the place where infrared waves fall.)
If you look at the electromagnetic spectrum, you will see that the frequency of infrared radiation is above that of microwave waves and below that of red. Its wavelength is longer than that of red, as mentioned above. The wavelength of infrared radiation is between 760 nm and 1 mm.
Infrared light
Just as light has different spectrums, infrared rays have different spectrums (not visible to the naked eye).
- Short-wave infrared radiation is called near-infrared radiation. Near-infrared waves are the spectrum closest to visible light. Without significant heat emission, there is no ability to see with the naked eye. This near-infrared radiation is the infrared radiation used in TV remotes.
- Infrared radiation with a longer wavelength is called Far Infrared. He is stuck with microwaves, which generate intense heat. The temperature of the sun The temperature emitted from the flame is caused by this far-infrared radiation. (It is called far because it is far from the red wave in the electromagnetic spectrum.)
Infrared radiation is one of the three ways of spreading heat energy. The other two methods are conduction and convection. Among these three methods, infrared radiation is the only one that can transfer heat without a barrier, so it can come through space. Therefore, the sun radiates heat to the earth and reaches it because the infrared radiation waves arrive.
In the universe, anything hotter than 5 degrees Kelvin (minus 268 degrees Celsius below the freezing point) emits infrared radiation. Our sun emits half of its energy as infrared radiation.
Infrared and home use
Electric ovens are used at home. Electric toasters heat food using infrared radiation. In the industry, there are six steps. Dryers use infrared radiation.
A typical home incandescent light bulb (a tungsten bulb, not an LED) can only produce about 10% of the energy it emits as light. The remaining 90% comes as infrared radiation.
You can communicate within a few hundred meters using infrared radiation. You can send text messages. In addition, TV remotes use infrared rays to communicate with the TV and control it.
Infrared surveillance equipment
One practical use of infrared is in infrared night vision devices and surveillance equipment.
All objects on Earth emit infrared radiation. The infrared waves emitted from these objects can be detected and reproduced with the help of electronic sensors.
Night vision binoculars are equipped with charge-coupled device (CCD) imaging chips, similar to those found in our phone cameras and digital cameras. The difference between the phone camera and the image capture chip is that this chip can sense infrared radiation.
By re-imaging the infrared rays captured by this CCD sensor, I re-image the night scene. These infrared cameras can be made small enough to be easily carried. Infrared night vision goggles and night vision binoculars mounted on guns are being used.
Astronomy and Infrared
Infrared detection is very useful in astronomy. All objects in the universe emit infrared radiation. Objects that cannot be seen by ordinary light can be captured and searched for by infrared radiation. Also, since light cannot be blocked by dust clouds, we can study the detailed structure of the objects behind the dust cloud nebulae.
Low-temperature objects in space do not emit light, so it is not easy to find and study them from a distance. But these objects emit infrared radiation. We can capture this infrared radiation and search for these objects. In this way, Comets, meteorites, and asteroids were discovered.
Dust from space, Infrared waves are used to study gas clouds and particles in the vacuum.
The main advantage of infrared waves is that they are not scattered by gas and dust like light waves. Infrared waves can pass through small dust particles, so they are very useful in studying the gas and dust surrounding objects in detail.