A region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1mm
Questions tagged [infrared-radiation]
288 questions
60
votes
6 answers
Why do we feel heat from infrared light but not from shorter wavelengths?
My guess would be that light with a higher energy such as visible or UV would feel hotter, but this is not the case!
Is this something to do with human senses or is there a physics explanation?
Giulio Crisanti
- 2,060
52
votes
4 answers
Why don't we use infrared light to heat food?
Why don't we use infrared (IR) or even the far IR just to heat food in a microwave oven instead of, of course, the conventional 2.45 GHz microwaves? Don't people call IR heat waves?
ObsessionWithElectricity
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36
votes
10 answers
Why are only infrared rays classified as "heat rays"?
I've often heard that Infrared rays are called "heat rays". However, I feel like this term is a misnomer. Don't all the wavelengths of electromagnetic radiation carry energy?
Judging by how gamma rays are highly penetrating and are dangerous when…
Cross
- 3,360
31
votes
6 answers
How does Infrared Relate to heat?
I never understood the relationship between Infrared and Heat. Is IR emitted when heat is generated, is heat generated when IR is made, and how do the two relate?
Skyler 440
- 461
26
votes
5 answers
Why can some electromagnetic waves heat things up while others cannot?
I have read that heat radiation happens in the form of infrared, which is an EM radiation with a longer wavelength than visible light. So the heat radiation that you can feel in an oven or under the the sun is actually the infrared portion of the…
NurShomik
- 371
22
votes
2 answers
Why does my infrared thermometer say the sky is at -2 °C?
I just got myself an infrared thermometer. I wouldn't have been able to predict what temperature it would give me when pointing at the sky, but it turned out to be -2 °C the first time I measured, and slightly going up and down with the temperature…
doetoe
- 9,484
17
votes
4 answers
Why do moving particles emit thermal radiation?
While answering another question about heat in an atom, the discussion in the comments led to the question of how heat is related to thermal radiation picked up by infrared cameras. The answer is that molecules undergoing translational motion (which…
tpg2114
- 16,815
17
votes
1 answer
Why does the sun "beat down" harder in the summer - or does it?
I know that seasons are caused by the Earth's axial tilt - in summer, latitudes away from the equator receive more surface irradiance (power per unit area), and vice versa in the winter, because of the closer-to-normal incident angle of the sun's…
TypeIA
- 318
16
votes
4 answers
Why does the light of this infrared laser become visible after reflection?
We use a 780 nm laser in our lab, and that makes it in the near infrared (IR) range. The majority of people can not see this wavelength of light. However, when the beam reflects off of an object (see image), the light becomes visible. This image has…
jamie1989
- 1,846
16
votes
9 answers
Why can't we see infrared light?
While explaining to my nephew about the physics of light, I told him we cannot see infrared color, and he kicked back with a very simple question: why can't we see it? I could not tell him. Is the human eye unable to sense such light or can it…
alvaroc
- 271
16
votes
5 answers
What common materials absorb most infrared light?
I'm competing in a simple robotics competition where most of the participants use reflected infrared light to detect their opponent. I'd like to make my own robot as difficult to see as possible. What common materials (fabric, plastic, paint, etc)…
Cerin
- 302
15
votes
3 answers
Why can a regular infrared camera not show temperature (thermography)?
There are a lot of questions here dealing with infrared cameras and thermographic cameras. I think I understand the reason why a thermographic camera is able to retrieve the temperature values from any object and convert them to a falsecolor…
flor1an
- 275
13
votes
2 answers
DIY Spectrophotometer doesn't work properly in the IR range
I've built an optical spectrometer by following the instruction given on the Theremino website: Theremino_Spectrometer_Construction.pdf, but I'm having a little issue with it.
Everything works perfectly fine from UV to red wavelengths, but whenever…
Matthew_R
- 321
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12
votes
5 answers
Why does an infrared thermometer display very low temperature when being directed to the outer air?
I'm toying with an infrared thermometer - one which you point onto an object, press the button and it instantly measures the temperature by estimating the infrared radiation from the object. It shows more or less the room temperature when I point it…
sharptooth
- 841
12
votes
3 answers
How can IR cameras see things colder than the camera?
I’ve read that only cold-blooded animals develop IR vision to spot warm prey because a mammal would blind himself with his own heat and not be able to see anything.
But I’ve seen a FLIR camera, operating at room temperature, able to image warm and…
JDługosz
- 5,357