What is the link between heat an infrared radiation?

Question

Does heat create infrared radiation? Is heat itself IR radiation? Is it radiation like I am thinking of in the sense of nuclear radiation except not harmful? If someone could clear this up for me...what exactly is the link here?

Really good answers so far. You guys sure know your IR.

Answer 1

Heat is a form of electromagnetic radiation that we can't see but of course we can sense. It is less energetic than the light that we can see, and not harmful per se. The dangerous spectrum is higher energy than we can see UV leads to Xray to Gamma ray.
The exception is in a microwave oven which generates very high intensity radio energy in the infrared spectrum at the resonant frequency of water molecules.

Answer 2

Look at the definition. Heat is the energy transferred between bodies at different temperatures. Electromagnetic radiation is only one way to transfer that energy. Conduction and convection and chemical reactions are others. Infrared is only a small part of the electromagnetic spectrum.

Nuclear radiation is completely different. While radioactive elements emit some electromagnetic radiation in the form of gamma radiation, most is particle radiation.

Answer 3

Anything with a temperature above absolute zero generates electromagnetic radiation. The frequency distribution of the radiation depends on the temperature. See http://en.wikipedia.org/wiki/Black_body

At room temperature, almost all the radiation is in the infra-red and lower. At temperatures over 1000ºK there will be some visible (mostly red) radiation; at 2700ºK the light will be yellowish-white, like a standard light bulb.

The radiation produces heat, but is not heat. Heat is the kinetic motion of molecules in a material. The radiant energy is absorbed by materials and converted to molecular motion, which we sense as heat.

Nuclear radiation are much higher frequencies, well above visible light, consisting of x-rays and gamma-rays. The energy of this radiation is enough to break apart atoms (ionize them). This type of radiation is harmful.

The difference in all these radiations is the frequency. See http://en.wikipedia.org/wiki/Radiation_spectrum

Answer 4

Infrared radiation is popularly known as "heat" or sometimes "heat radiation," since many people attribute all radiant heating to infrared light. This is a widespread misconception, since light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun only accounts for 50% of the heating of the Earth, the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visible radiation. It is true that objects at room temperature will emit radiation mostly concentrated in the 8-12 micron band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see black body and Wien's displacement law).

Heat is energy in transient form that flows due to temperature difference. Unlike heat transmitted by thermal conduction or thermal convection, radiation can propagate through a vacuum.

The concept of emissivity is important in understanding the infrared emissions of objects. This is a property of a surface which describes how its thermal emissions deviate from the ideal of a blackbody. To further explain, two objects at the same physical temperature will not 'appear' the same temperature in an infrared image if they have differing emissivities.

Answer 5

1st of all.... heat is the energy. its the value... a quantitative term. when a particular substance burns, all the atoms of that go into an excited state of energy. this leads to increase in the temperature, as the atoms try to stabilise themselves and looseup the energy. During this state the electrons may radiate in the frequency in the range of IR. these rays have enough of the energy to heat up the materials coming between its way. Thus both of them have a connection, but its to be remembered that every heat doesn't produces IR, but each wave of IR does produce heat.

Answer 6

When infrared radiation hits the body we feel it as heat. The more infrared radiation an object gives off, the hotter it feels.

Answer 7

Infrared radiation is the release of heat.
Everything can produce infrared radiation include us.
Some produce less while some release more heat.