Can Interferance cause magnification?

AI Thread Summary
The discussion centers on a unique optical phenomenon observed with a vinyl fence that creates a striking black and white interference pattern when viewed from a distance. As the observer approaches, the image appears magnified and detailed, resembling a negative of the fence. Questions arise about whether this effect is a common feature of interference patterns and if it can be captured in photographs. Participants express interest in understanding the mechanics behind the phenomenon and suggest further investigation through closer observation. The possibility of optical illusions is also acknowledged, prompting a plan for a more deliberate examination of the effect.
pallidin
Messages
2,207
Reaction score
3
There is this house down the street which has one of those new, white plastic vinyl fences around the front yard.
This particular fence is constructed in such a way as the vertical members are the width of the spacing between members(about 2 inches or so)
More importantly, the top of the fence line changes horozontaly, kind of like a wave(I suppose for aesthetic reasons) with some ornamental du-dad fashioned atop each vertical fence element.

Anyway, when I drive to work each morning, the sun is above and behind the fence.
I notice the interferance pattern, but a startling thing happens as I approach, roughly, about 100 feet from it:
A black and white interferance image of the back fence, with all the du-dads, appears with exceptional crispness and is about 4-times larger(width-wise) than the fence itself.
It is an awesome sight, an have seen it hundreds of times. It appears as though I am looking at a magnified negative image of the back fence with exquisite detail. When the sun is not behind it the image is barely noticable.
Is this a common feature of interferance patterns?
Also, if I take the time to take pictures, will the phenomenon show up?
 
Science news on Phys.org
I should point-out that the exceptionally fine detail I see is with respect to the outline of the back fence and top du-dads. No "non-edge" detail is observable.
 
Well, if your eye can see it, so can a camera...

- Warren
 
Do you mean magnification of the fringes (by your first topic)?
 
Where does the pattern appear? That's the only thing i can't follow. Sounds interesting though. Can you snap a few pictures?
 
I'm thinking what sporff is too [unless I misunderstood your message].

In my Serway, it says that interference patterns only occur when the spacing between the slits is approximately that of the wavelength of the EMR.
 
Thanks all, I've been away. I will more closely examine this to correct or further address the issue.
I am not sure that this is not some type of optical illusion or mis-interpretation on my part. Nonetheless I will endeavor to more accurately experience the event(it has previously always been by a moving car), so I will do a "walk-by" in the next week.
 
Back
Top