Shadow pattern from light through a cracked door

  • Context: High School 
  • Thread starter Thread starter Chrono_13
  • Start date Start date
  • Tags Tags
    Light
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
Sign up Log in
7 replies · 2K views
Chrono_13
Messages
4
Reaction score
0
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.
 

Attachments

  • Wierd.png
    Wierd.png
    73.5 KB · Views: 527

Discussion

Physics news on Phys.org
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.
 
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.
 
Without knowing the details of your door and room, we can't say for certain what's causing it.
 
Chrono_13 said:
The light source is the sun, and it’s a single pane window in the room.

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

And it better be straight lines and to scale, or he's getting points taken off!
 
  • Like
Likes   Reactions: davenn
Drakkith said:
And it better be straight lines and to scale, or he's getting points taken off!

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
 
  • Like
Likes   Reactions: Drakkith
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.