Infrared and Heat

[fordyjohn]

Can anyone tell me is IR and Heat the same

[MetaFrizzics]

InfraRed is a name used to describe a small band of frequencies near the visible red spectrum. We perceive infra-red waves as heat, because when they are absorbed by objects (like food or skin) the energy from these Electromagnetic (EM) waves is usually converted for the most part into 'heat'. That is, the temperature of the absorbing material is raised.

 

What is 'temperature'? Well, it's the average speed of a group of atoms or molecules, and it shows up as a distributed Bell curve. That is, if you had a box full of gas molecules, they would all be travelling through space at different speeds and directions in a more or less random distribution or pattern, with most of the speeds in the middle (average) and hence the Bell curve. Some of the motion of these molecules will also be contained or exchanged as rotational motion, and vibrational motion.

 

(How can you have vibrational motion in free space? Easy: Imagine a diatomic molecule, e.g. H2, that is a molecule made up of two atoms. If the bond holding them together is 'springy', then the two atoms can stretch apart and bounce together like balls on the end of a slinky, and this means some energy can be stored in this bond as a kind of accordian-like motion, even in free space.)

 

When the average speed of the molecules in a box is raised, those molecules hit the side of the box harder, and if we touch the side it feels hotter. So energy, temperature, and average random motions (translational, rotational, vibrational) are all related but slightly different concepts and ideas or ways of looking at the same thing.

 

In answer to your question, you might as well consider the infra-red rays coming from a 'heat-lamp' as heat, since most of the energy will be converted to heat in the form of raised temperature of an object under the lamp.

[danny8522003]

The distributed bell curve is called a "Maxwell-Boltzmann Distribution Curve" and looks something like this

[fordyjohn]

Ok so IR produces heat but are they one in the same, can you not have one without the other.

[Klaynos]

IR is the name of a band of frequencies for EM radiation.

 

Heat is the transfer of thermal energy due to a temperature difference between the two. There are 3 main types of heat transpher, Radiation, Convection and Conduction. For radiation the frequency of the EM radiation it refers too is very offten in the IR band. (Heat is to thermal energy, as work is to kinetic energy or something like that)

 

Are they the same, NO!

[swansont]

InfraRed[/b'] is a name used to describe a small band of frequencies near the visible red spectrum. We perceive infra-red waves as heat, because when they are absorbed by objects (like food or skin) the energy from these Electromagnetic (EM) waves is usually converted for the most part into 'heat'. That is, the temperature of the absorbing material is raised.

 

This is true of any absorbed electromagnetic radiation

 

What is 'temperature'? Well, it's the average speed of a group of atoms or molecules, and it shows up as a distributed Bell curve. That is, if you had a box full of gas molecules, they would all be travelling through space at different speeds and directions in a more or less random distribution or pattern, with most of the speeds in the middle (average) and hence the Bell curve. Some of the motion of these molecules will also be contained or exchanged as rotational motion, and vibrational motion.

 

Actually, for a gas they show up as a Maxwell-Boltzmann distribution, which is not a bell (Gaussian) curve, since it is necessarily bounded by v=o but not bounded by a maximum.

 

...

 

In answer to your question' date=' you might as well consider the infra-red rays coming from a 'heat-lamp' as heat, since most of the energy will be converted to heat in the form of raised temperature of an object under the lamp.[/quote']

 

Absolutely not.

 

Hot things radiate strongly in the infrared. But any energy transfer due to a temperature difference is heat. You can burn things with visible light, a fact to which I can personally attest, and to which numerous ants could, too, if they could communicate in a way we could understand.

 

I imagine someone will one day commercialize a device that uses even longer wavelength radiation than IR to heat things up, in, say, the microwave region of the spectrum. They will name it the "longer than IR wavelength oven" or some such.

 

Infrared and heat are most definitely not synonymous.

[Jacques]

I imagine someone will one day commercialize a device that uses even longer wavelength radiation than IR to heat things up, in, say, the microwave region of the spectrum.

It is called a microwave oven

[swansont]

It is called a microwave oven

 

Yes. And it was called sarcasm.

[MetaFrizzics]

I just spent four hours designing one, and now I notice you were being sarcastic.

My bad. I guess this battery that runs on garbage is also a dumb idea.

[insane_alien]

UV light can burn those silly people who spend too long lounging in the sun.

I have and infrared spotlight typ thing made out of L.E.D.'s but if you put your hand in it it doesn't feel hot. its a high frequency IR lamp like what comes out your remote control.

[swansont]

UV light can burn those silly people who spend too long lounging in the sun.

I have and infrared spotlight typ thing made out of L.E.D.'s but if you put your hand in it it doesn't feel hot. its a high frequency IR lamp like what comes out your remote control.

 

It all comes down to how much energy gets deposited per unit area per unit time

[insane_alien]

well the ir spotlight appears really bright on an infrared camera but i don't know if thats image enhancement or what.