How Does Infrared Work?

Color, electromagnetic waves and heat levels are very closely related; a fact that we don’t always consider when we use everyday objects. For example, red light has different temperature levels and wave lengths than blue light, green light or any other color of light. This basic information is important to our understanding of infrared technology.

The name “infrared” means below red. The term “infra” comes from the Latin language and indicates where infrared fits on the color spectrum. We can see the color red. It is in the range of visible light and has the longest wave length. Infrared, however, is not visible to the human eye.

Same, Only Different

Infrared actually has a few various levels – short wave, high density; medium wave, medium density; long wave, low density. Depending on the intended use, one of these types of infrared energy can perform specific tasks, such as transmitting a signal over a certain distance. Remote control devices for our electronic equipment generally rely on infrared signals that are sent out as pulses of this invisible light.

We can also get a better understanding of infrared by thinking about the energy given off by objects as heat. An object that we might say is “burning” is giving off heat as visible light. Objects can give off energy as invisible light, usually in the infrared spectrum. Scientists have harnessed this type of energy for use in industry, medicine and many other fields.

For example, thermal imaging is based on infrared technology. A sensitive camera can measure temperature to the fraction of a degree and convert this information to the color spectrum. The warmest parts of the object show as red, then yellow, and so on to the cooler parts of the spectrum. In many cases, diseased tissue in the human body will show as red or a shade that is different from healthy tissue.

Can’t See?

We mentioned that the human eye cannot detect infrared or other invisible colors. However, sensitive electronic equipment, such as night-vision goggles, can detect heat energy in the infrared area. If you are wearing these goggles you can “see” objects that would not otherwise be visible in the dark conditions. Infrared technology is also used in other military situations, as well as in determining where “hotspots” might be in forest fire conditions. Astronomers also use this information when studying the light given off by distance objects in space.

Intricate knowledge of infrared technology also helps when choosing materials for building and insulating heating devices, convection ovens and so on. When thinking about how infrared works, keep in mind that higher temperatures go hand in hand with shorter wavelengths. This is what separates visible red from invisible infrared.