Above, A Basic Demonstration of Optical Cloaking. Cloaking is a term for hiding an object from view at specific frequencies, but evidently one can cloak things DIY-style with four mirrors and their precise placement.
So before reading further, how is the illusion above happening? Any guesses?
Professor of Physics at the University of Rochester John Howell and his 14 year-old son Benjamin built three uni-directional optical cloaking devices with everyday materials. For around $150, they put together “one made of Plexiglass and water, another of inexpensive lenses, and a third constructed using ordinary mirrors.” The video demonstration above shows one of the devices and two of his sons… sometimes.
What might this small feat of optical engineering be used for? Since it’s uni-directional it has limitations, but in theory, it could hide satellites orbiting Earth. You can read more about how Professor Howell’s devices work in the videos notes, here on arXiv.org, or on MIT Technology Review.
There are also a few more videos with mirrors in the archives.
Thanks, @AmebaCuriosa.
Here’s an excellent discussion starter… what is happening to the liquid in this video?
This is Supermajor, a project by teacher and artist Matt Kenyon that was inspired by the BP Deepwater Horizon oil spill. From the project:
In the gallery a wire rack of (vintage) oil cans sits. One oilcan has a visible fissure out of which oil slowly flows cascading onto the pedestal and gallery floor… The only thing is, the oil isn’t exactly flowing out of the can. Instead, oil appears to slow slowly drop by drop back into the can. At times the drops of oil hover unsupported in midair. Other times the drops are in the process of a slow motion splash onto the pedestal.
I don’t know exactly how this demonstration is being executed, but I might suggest watching some of these videos next… and definitely watch this one…
There’s also an interview with Kenyon over at Cool Hunting and FastCo Design, and more projects at Swamp.nu.
Thanks, @AmebaCuriosa.
This mind-bending and water bending viral video is another experiment from Brusspup (featured previously on this site). Here’s the zig zag DIY:
Run the rubber hose down past the speaker so that the hose touches the speaker. Leave about 1 or 2 inches of the hose hanging past the bottom of the speaker. Secure the hose to the speaker with tape or whatever works best for you. The goal is to make sure the hose is touching the actual speaker so that when the speaker produces sound (vibrates) it will vibrate the hose.
Set up your camera and switch it to 24 fps. The higher the shutter speed the better the results. But also keep in the mind that the higher your shutter speed, the more light you need. Run an audio cable from your computer to the speaker. Set your tone generating software to 24hz and hit play. Turn on the water. Now look through the camera and watch the magic begin. If you want the water to look like it’s moving backward set the frequency to 23hz. If you want to look like it’s moving forward in slow motion set it to 25hz.
And if you want to see it with your eyes and no camera, a strobe light, set to 24hz in a light-controlled environment should do the trick.
We love illusions and experiments. Another great video on tricking the eye at the right frame rate: Pixar’s Zoetrope and how animation works.
via Colossal.
