Over the last few years, the science behind optics has been perused by many scientists in an attempt to classify light’s fellow electromagnetic waves. As the production and properties of these waves were under study, innovators almost parallely began producing the waves artificially for other purposes.

In 1800, Sir Fredrick William Herschel, a renowned musician and astronomer made a dazzling discovery that had a dramatic impact in the field of communication, Medicine and astronomy.

In an attempt to measure the temperature of different colors, Herschel directed sunlight through a glass prism and measured the temperature of each color using a blackened thermometer. During this analysis, he observed that a portion beyond red light that was devoid of sunlight had the highest temperature.

On further study of these waves, Sir Herschel found that they were reflected, refracted and transmitted. Due to their high temperature, he labeled them as “Calorific rays”.

Theses rays of light, commonly called the infrared waves, have played a major role in different fields, carving itself a niche in the applications of science.

Facts about Infrared Rays:

1. The origin and meaning of word “Infrared Waves”.
The word “Infrared” originated from the Latin word “Infra” meaning below. These rays are further called waves, owing to their electrical and magnetic properties and are classified as one among the many electromagnetic waves. These rays have wavelengths ranging from 10-6 to 10-2 meters and are present right below the red portion of visible light in the Electromagnetic spectrum series.

2. Infrared rays are classified under non-ionizing radiation.
Non ionizing radiations are defined as those that do not carry energy in them to ionize atoms of the object they interact with. Though incapable of releasing an electron from the crystal lattice, these radiations may have sufficient energy to excite molecules resulting in vibrations.

3. The infrared regions.
Infrared waves may be further classified in to 3 regions:
Far Infrared Region: 10 micrometers to 1 millimeter. This region of the IR waves overlaps with microwaves. They are most significantly used in astronomical applications.
Mid Infrared Region: 10 micrometers to 2.5 micrometers. These waves are most significantly used in imaging applications.Near Infrared Region: 2.5 micrometers to 750 micrometers. These waves are most significantly used in diagnostic applications.

4. Humans are sources of Infrared waves.
Infrared rays are emitted by all objects at near room temperature. The human body is at a temperature of 37 degrees Celsius. At this temperature, all the associated atoms in the body move around giving rise to thermal energy. The body thus acts as a thermal source producing infrared waves.

5. Heat produced by fire is due to infrared waves.
Warm objects radiate Infrared waves. Warmer the object, higher the energy and hence frequency of emitted waves. Fire, due to its greater temperature acts as a heating element to produce infrared waves that are further responsible for the warmth produced.

6. Infrared ovens- the first ovens.
In earlier days, infrared ovens were the most widely used electronic gadgets to heat food. They were made of an infrared producing infrared burner that excited molecules and increased their temperature. This method of heating was highly effective as no heat was lost and infrared rays were capable of heating grills up much faster than normal. The hot air however dried the food up and these ovens were thus replaced by the present microwave ovens.

7. Infrared radiation measuring devices.
Infrared rays do not belong to visible region of electromagnetic spectrum and can thus not be seen by naked eye. The rays and its effects can however be measured by various other measuring devices.
The infrared spectrophotometer measures absorption of IR waves by molecules as a function of wavelength and time. This gives information of the structure of molecules under study.

8. Applications of Infrared in medicine.
Infrared waves have various diagnostic and therapeutic applications some of which include:
• To relieve pain and enhance healing.
• To decrease soreness, swelling and numbness.
• To lessen body odor and perspiration of area under treatment.
• To provide localized warming.
• Infrared thermometers.

9. Application of Infrared in Communication.
Infrared rays are very commonly used in remotes. The remote produces Infrared waves in the form of pulses that represent digital data. These waves are further sensed by an IR sensor that decodes the digital data to binary information that is read and processed by the instrument’s microprocessor.

10. Thermal imaging of supernatural elements!
It is widely believed that the use of infrared waves can be extended to image supernatural elements. Supernatural science explains that the presence of a spirit is indicated by a cold spot. On irradiating these spots with IR light, the spirit absorbs kinetic energy and these cold spots can be measured using infrared thermometers and imaged using infrared cameras.