Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can you see IR?

  1. Yes I can.

    55.9%
  2. No I can't.

    44.1%
  1. Sep 29, 2006 #1

    DaveC426913

    User Avatar
    Gold Member

    I learned here on PF that some people are sensitive to lower frequency light than others. In fact, some people can see well into the infra-red range.

    I was very skeptical, so I tested it out. I was right, I cannot see IR. However, to my astonishment, my son can!

    Here is my experiment, which I encourage you to try. I'd love to know.

    1] Get really dark - throw a heavy blanket over your head or go into a dark room.
    2] Point your remote at your face. Press some buttons. Note if you see the red light or not.
    3] (the enhanced-assisted version) To ensure you're not fooling yourself - have someone else press the buttons so you can't anticipate on-ness or off-ity.
     
  2. jcsd
  3. Sep 29, 2006 #2

    JasonRox

    User Avatar
    Homework Helper
    Gold Member

    I shall try that out one day.

    I doubt I can see it though.
     
  4. Sep 29, 2006 #3
    I can't, I've tried before...although it wasnt a perfectly dark environment...
     
  5. Sep 29, 2006 #4

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Do all remote controls use the same LED? A 50 nm shift in the emission spectrum can make the difference between "Eureka, I see it!" and "Ugh, can't see squat!"
     
  6. Sep 29, 2006 #5
    If it's too dim, try pointing a 50W infrared laser directly into your eye. You might be able to detect that.
     
  7. Sep 29, 2006 #6

    DaveC426913

    User Avatar
    Gold Member

    Yeah. this is the big flaw in my experiment.

    However, I have demonstrated to my satisfaction that the phenom is real since my own experimentation used the same remote. Of four people in my house, three could not see it, while one could.
     
  8. Sep 29, 2006 #7
  9. Sep 29, 2006 #8
    How sure are you? Are there any other (visible) lights on the remote? Was the experiment controlled against dishonesty?
     
  10. Sep 29, 2006 #9
    of course I can
     
  11. Sep 29, 2006 #10
    I don't think I can. I tried an experment in my bathroom and I couldn't see anything but there was some light comming form the door, so I might try again in my garge.

    I wonder if it's possible to get to train your eyes to see infrared(It just would be cool to se infrared light)?
     
  12. Sep 29, 2006 #11

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    Some are fairly bright, and can be seen in dim lighting.
    Others are extremely dim and it has to be dark to see them.
    Don't know if it's power or wavelength that makes the difference. Perhaps both.

    The one out of 10 I can't see probaby has almost dead batteries, since its gotten real picky about pointing.
    Maybe I'll find some new ones and try it again.
     
  13. Sep 29, 2006 #12

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    Well that's one :smile:
     
  14. Sep 29, 2006 #13

    DaveC426913

    User Avatar
    Gold Member

    I made sure. I did the experiment a second time after ensuring I'd controlled it specifically against dishonesty.

    No other visible lights.
    I ensured it was pitch dark.
    I held the remote and pressed the button rapidly and randomly.

    Every time, he immediately said 'on' or 'off' - he didn't even have the decency to be hesitant :grumpy: :grumpy: . He got it right no matter how many times I tried it or how fast I did it. In fact, we went under the blanket together and I did the experiment. He still got it right every time, and yet I could see nothing. Once we took the blanket off, he showed me where the LED was situated within the little window.
     
    Last edited: Sep 29, 2006
  15. Sep 29, 2006 #14

    Math Is Hard

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I definitely see it. It is faint, but clearly there.
     
  16. Sep 29, 2006 #15

    Math Is Hard

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

  17. Sep 29, 2006 #16

    Danger

    User Avatar
    Gold Member

    Totally expecting failure, I took the remote for the TV into the bathroom just now and the damned thing was bright as day (okay, not quite). W asked me what I was doing, so I pointed it at her and asked if she could see the light. This was in the living room with the TV, the kitchen light, and the neighbourhood lights coming through the balcony doors. She saw it fine, so I turned it around and saw it quite plainly even in that ambient light. :bugeye:
    MUTANTS, UNITE!
     
  18. Sep 29, 2006 #17

    DaveC426913

    User Avatar
    Gold Member

  19. Oct 5, 2006 #18
    One of my remotes has a red 'signal on' light that goes on in addition to the IR emittin bulb. I could see this 'signal on' light in the back ground of the IR bulb, so I say beware of your remote and double check it. My other remote had no 'signal on' light and I could see the IR in light out conditions.

    Dave, I suggest blacking out your kitchen, turning on your stove element, standing beside your son and seeing the difference in your IR threshold. Your son would beat you by a few seconds I'd guess. If you were especially into it, you could get a hold of your stove's specs and derive a solution for how long a second of delayed observation equals in terms of element temperature and finally of the wavelength emitted.

    I think my element goes from 0 to 10 (max) in about 90 seconds. At 10 the element appears to be a orangy-red (more orange than red). I'm guessing its temperature at 10 is ~800C. At a setting of 0 (off), the element is roughly room temperature 20C. I'm not sure what material it is which would be critical to calucating its heating curve.

    Anyways, just a thought.
     
  20. Oct 6, 2006 #19

    DaveC426913

    User Avatar
    Gold Member

    Yup. Same here. I used the non-cheating one.

    Yeah that's a pretty iffy way of doing it though. Very prone to "overanticipation" and even "cheating". I also doubt it would be slow enough to observe much difference between us that wouldn't be swamped by reaction and perception times.

    If he says "now" and I sat "now" two seconds apart, is that pretty much the same time or is that a significant difference?
     
  21. Oct 6, 2006 #20
    Just for the hell of it, try having your son adjust the heat control to the point where the light first becomes visible to him. Mark it. Then, do this yourself, and see if there is any noticable difference between the marks.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Can you see IR?
  1. I See You! (Replies: 2)

  2. I see you (Replies: 20)

  3. Can you see the stars? (Replies: 46)

  4. What do you see? (Replies: 85)

Loading...