Goldfish bowl reflecting inside into apparent 3-D

  • Thread starter Nick Levinson
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In summary, there was an optical illusion involving a box with a jewel at the bottom that appeared to be at the top due to a curved mirror inside the box. Despite the explanation, the person is still unsure why there aren't more similar illusions known.
  • #1
Nick Levinson
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I saw an optical illusion once decades ago that I don't think I've seen written up anywhere else. I don't even know what to call it, so I can't very well Google it.

A box about three feet tall and about a foot square on top had a large hole on top. Looking down inside it, we could see a jewel. An invitation to help ourselves was posted and a nice person told us to go ahead. We tried. My hand went through the jewel like it didn't exist. Then we read the sign in small print.

Basically, in the top of the box was something like a goldfish bowl, but it was coated on the outside so that it had mirror surfacing inside. The jewel was way down at the bottom. What we saw was near the top, so we reached near the top and I felt nothing and my friend probably felt nothing, too. The explanation in the sign was that the jewel was being reflected from the bottom to the top, thus was only an optical illusion at the top.

My problem with this explanation is that, by now, I should have seen or heard or read of dozens of similar illusions in various places.

What was really going on?
 
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  • #2
I've forgotten the exact description but it's a simple effect of curved mirrors and precise placement of the object. I also can't help with the name but I'm sure there are dozens of illustrations on the internet if we knew what to look for.
 
  • #3
http://practicalphysics.org/optical-illusion-concave-mirror.html?
 

1. How does a goldfish bowl create the illusion of a 3-D image?

The curved surface of a goldfish bowl acts as a convex mirror, reflecting light in a way that creates the appearance of depth and dimension. This effect is known as anamorphosis.

2. Why does the image inside a goldfish bowl appear distorted?

The curved shape of the bowl causes light rays to bend and distort as they reflect off the surface. This distortion creates the illusion of a 3-D image, but it may appear stretched or warped.

3. Can the same effect be achieved with any curved surface?

Yes, the anamorphic effect can be achieved with any convex mirror or curved surface, such as a spoon or a polished sphere. However, the shape and size of the surface will affect the quality and clarity of the 3-D image.

4. Can this illusion be seen from any angle?

The anamorphic effect is most prominent when viewed from a specific angle, known as the "sweet spot." This is the point where the reflection appears most clear and 3-D. Moving too far to the side or above the bowl may distort the image or cause it to disappear completely.

5. How is this phenomenon used in science or art?

Anamorphosis is used in various fields, such as photography, cinema, and visual arts, to create unique and intriguing images. In science, it is used to study the behavior of light and how it interacts with different surfaces. In some cases, anamorphosis can also be used to create optical illusions or hide secret messages in art.

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