1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Shadows in light

  1. Feb 16, 2016 #1
    So I wake up this morning and find this on my floor, peeking out from a door cracked open. Now I’m not scientist but I’m not unfamiliar with the simple workings of physics. I can’t quite pin down what is going on here. I’m familiar with how light can bend around things and I considered the possibility what I could be seeing here is just light reflecting off the white walls of the room inside.

    Both possibilities just didn’t feel completely right.

    Ahh how simple things in life can be so confounding… I'd appreciate it if someone can help me understand what I'm seeing here.
     

    Attached Files:

  2. jcsd
  3. Feb 16, 2016 #2

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Hi Chrono, :welcome:

    My best guess is there are two light sources at the other side of the door: a window with a stile, or a door and a window.
    Hve you ever heard of a pinhole camera ?
    Here the narrow door opening might function as a slit camera: not a 2d picture as with the pinhole, but a 1d light/dark stripes pattern.
     
  4. Feb 16, 2016 #3
    The light source is the sun, and it’s a single pane window in the room. I am a little familiar with pinhole cameras though I don’t believe that’s what happening here. I’m familiar with the “folding” effect light can have when it gets bent and it makes it appear to create shadows by contrast. But this dark spot is so sharp I can’t explain it with that reasoning.
     
  5. Feb 16, 2016 #4

    Drakkith

    User Avatar

    Staff: Mentor

    Without knowing the details of your door and room, we can't say for certain what's causing it.
     
  6. Feb 17, 2016 #5

    davenn

    User Avatar
    Science Advisor
    Gold Member

    draw a floor plan of your room showing window, door where on the floor this image is in relation to those 2 things

    make sure everything is orientated correctly


    Dave
     
  7. Feb 17, 2016 #6

    Drakkith

    User Avatar

    Staff: Mentor

    And it better be straight lines and to scale, or he's getting points taken off!
     
  8. Feb 17, 2016 #7

    davenn

    User Avatar
    Science Advisor
    Gold Member

    hahaha

    I was thinking photo, but may be difficult to get whole room in unless a wide angle lens is used and scale would then be shocking haha



    D
     
  9. Mar 1, 2016 #8

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    Is it just me but I don't see anything unusual in the photo. Try opening any closing the gap in the door to see how it varies.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook