Final answer:
Infrared radiation is perceived as heat due to its longer wavelengths beyond the visible spectrum and can be detected by specialized devices. It is utilized in various technologies due to its unique properties that allow us to comfortably absorb it, enabling applications such as heating, night vision, and medical imaging.
Step-by-step explanation:
When you stand in front of an open fire, the type of electromagnetic radiation you sense as heat is infrared radiation. Infrared radiation is different from visible light waves as it has a longer wavelength and cannot be detected by the human eye. In fact, the term 'infrared' means 'below red', indicating its position just below the visible red light in the electromagnetic spectrum. Unlike visible light, all objects emit infrared radiation depending on their temperature, and this emission obeys the Stefan-Boltzmann law, which relates to the fourth power of an object's absolute temperature.
Infrared radiation is also employed for various practical uses, such as in quartz heaters which preferentially warm us more than the surroundings because we absorb infrared better. This property is utilized in night vision technology and medical thermography. For instance, law enforcement and military use night scopes to detect individuals by their infrared emissions. We perceive infrared as heat, not as sound or static, because of our skin's high emissivity in the infrared spectrum, making us capable of easily feeling this type of radiation.