The trickery of prisms strikes again! Here two hunks of Dove plexiglass fit over a pair of glasses' eyepieces to invert all images the wearer sees. Reversing Goggles make for interesting school science experiments, as in the above video, as well as fun ways of flooding oneself with frustration, or screwing with people who are high.
Goings-on in the world naturally fall upon human retinas upside down, but our great and powerful brains have adjusted to this joke of Mother Nature's and are able to right the images as we view them. Wearing the Reversing Goggles serves to test and F with our brains even more, flipping the flip to right side up back to right side down. The effect appears to be extraordinarily disconcerting, again as evidenced by the kids in the video boning all attempts to complete the simple task of writing their names on a board.
In the 1890s, scientist George Stratton postulated that wearing the Reversing Goggles indefinitely would prompt our brains to adjust to the new image feed, and invert the again. He was right. After 4 days, the world appeared righted. Of course, once he removed the glasses he was totally F'd, and had to wait out the reversing period again, a process which I'm pretty sure would make my own brain explode. If I didn't rip out my eyeballs first.
Suggestions for fun experiments to try while wearing the Reversing Goggles include shaking hands, picking up an object, and taking a leak. The prisms in these glasses also rotate 90 degrees to depict a left-right reversal instead of an up-down one.