Technically heat energy and light are different things, but heat energy can be measured by its EM radiation. Given enough temperature, heat can produce visible light as in our sun as well as ultraviolet as in our sun. Also, although heat energy and light are different things, heat energy produces radiation in the EM spectrum and most heat produced on earth produces light in the infrared.
Infra-red radiation includes emissions from single molecules or atoms, as a consequence of quantum mechanical transitions between energy states of those atoms or molecules. It also includes emission of a continuum spectrum of EM radiant energy from large assemblages of atoms or molecules that have a Temperature higher than zero kelvins; that radiation being entirely due to, and characterized by the Temperature of the material, and unrelated to any quantized energy levels that are characteristic of the emitting material.
The origin of the radiation is the acceleration of electric charge in the atoms or molecules of the material, while they undergo distortion as a result of being in collisions with each other; those collisions being characteristic of the Temperature of the material.
Heat energy can be transported through physical materials, as a consequence of the collisions between atoms or molecules and their neighbors. IR radiation is a consequence of the thermal energy of a system, and it is in this form that the energy propagates. Ofcourse, there are various regions in the electromagnetic spectrum and just about any one of them can carry energy in simple terms.
Doubtlessly, you must have heard of the microwave, which uses the radiation in the microwave spectrum to heat food. So, the relation between infrared and heat is that they can be said to be generated from each other. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Learn more. How does Infrared Relate to heat? Ask Question. Asked 8 years, 1 month ago. Active 4 years, 4 months ago. Viewed 55k times. Improve this question. Skyler Skyler 1 1 gold badge 4 4 silver badges 7 7 bronze badges. Heat can only be defined when there is a movement of thermal energy, and IR light cannot be emitted from "anything above absolute zero" it must be emitted from a system which has enough energy and the correct transition rules to generate a photon in the IR region.
Anything above zero kelvins, radiates EM energy, some will be IR, but not necessarily much. That heat energy excites the molecules in the object it meets which being to vibrate and gain energy and warm up. Far Infrared — unsurprisingly — the same band of infrared that the human body itself emits. All objects including people absorb and emit infrared and whether one is absorbing or emitting depends on the difference in temperatures between objects in an environment. If objects in an environment are warmer than you are, you will warm up from them.
If you are warmer than objects in an environment you will radiate out to them and feel cold. This Infrared emission is why police Infrared cameras can see fugitives trying to escape detection. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic. Far infrared waves are thermal. In other words, we experience this type of infrared radiation every day in the form of heat!
The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared. The temperature-sensitive nerve endings in our skin can detect the difference between inside body temperature and outside skin temperature. Shorter, near infrared waves are not hot at all - in fact you cannot even feel them. These shorter wavelengths are the ones used by your TV's remote control.
Humans, at normal body temperature, radiate most strongly in the infrared at a wavelength of about 10 microns. A micron is the term commonly used in astronomy for a micrometer or one millionth of a meter. This image which is courtesy of the Infrared Processing and Analysis Center at CalTech , shows a man holding up a lighted match! Which parts of this image do you think have the warmest temperature? How does the temperature of this man's glasses compare to the temperature of his hand? To make infrared pictures like the one above, we can use special cameras and film that detect differences in temperature, and then assign different brightnesses or false colors to them.
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