Spectral Decoder CD Art
Interesting band and incredible physics toy CD art:
From Amazon: BUY NOW Cassadaga CD
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Spectral Decoder CD Art: hidden images are revealed through ingenious and intricate Moiré pattern interference on the CD Cassadaga by the band Bright Eyes. Carefully align and slide the included transparent sheet of horizontal prisms (similar to a Fresnel lens) and the secret images pop into view giving insights and artistic renderings of the songs on this release. The Spectral Decoder process is patented and manufactured by 3D Images Ltd. of London. The accompanying music is the opening bars from the 8th track of this CD "Middleman".
Golden Ferrofluid
Available on Etsy: BUY NOW Gold Ferrofluid Cell
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Golden Ferrofluid: colloidal ferromagnetic liquid in a specially prepared water-alcohol suspension. Curious behavior results from the interplay between magnetic force and surface tension. I'm still investigating the gold coloring and the specific makeup of the clear suspension fluid- both trade secrets it seems. The gold color appears to be a thin coating at the boundary between the ferrofluid and the suspension liquid.
Spherical Dice
A must for any die/dice collectors:
From Amazon: BUY NOW Spherical Dice
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Click this link for other amazing dice featured on @physicsfun
Spherical Dice: these fair six "sided" dice are hollow inside with a ball that weights each sphere such that one of the six values is always on top. When these dice are rolled (literally!) the internal weight lands in one of six cavities inside creating a low center of mass which aligns one of the numbers to the top. Another low center of mass toy!
Caustic Projections from 3D Printed Optics
The optical element used in the video is an industry sample from Luximprint, a company that developed the 3D additive optical printing techniqe. Samples are available from thier shop:
From luximprint.com: 3D-Printed Optics Sample
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Wikipedia has a nice discussion of the optical phenomena of caustics
Caustic Projections from 3D Printed Optics: the intricate geometries of light due to refraction through various curved surfaces of transparent plastic. A 520 nm green laser pointer is refracted trough a sample optical element with surface features of triangle and square pyramids and convex lens elements- made to exhibit examples of additive optics fabrication for lighting applications. When light rays refract through a curved surface they concentrate into bright patches called caustics, often with cusp singularities (sharp points) and intricate threads of shadow.
Vortecon
Get one here:
From KickStarter: ORDER NOW Vortecon Kinetic Desk Toy
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Vortecon: precision machined kinetic desk toy with helical motion illusion. Give these massive cylinders of stainless steel or brass a spin and the imparted angular momentum (along with precision bearings) allows for sustained rotation. The spiral designs converts rotational motion to translational motion for a nice visual effect. Another exquisite design by Kristoph Krisjans.
Andris Tri-Zonal Space Warper
Available here:
From Amazon: BUY NOW Andrus Tri-Zonal Space Warper
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Magician and professor of psychology Richard Wiseman describes the genius of Jerry Andrus and the psychophysics of the Space Warper.
Andris Tri-Zonal Space Warper: Stare at the center of the spirals for at least 15 seconds- the next thing you look at will appear to be in motion. This spinning disk top features the famous illusion by magician Jerry Andrus that demonstrates aspects of the physics and psychophysics of our visual perception- specifically the part of our brain that detects motion. The effect is even stronger in person than in the video.
Curves of Constant Width
Get a set here:
From Maths Gear: BUY NOW Curves of Constant Width (set of 4)
Click here for 3D Solids of Constant Width
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Curves of Constant Width: regardless of the precise shape, any curve of constant width has a perimeter equal to pi times its width! These convex shapes will roll because like a circle they have the same diameter from one side to the other no matter their orientation. Here are two famous examples: the Reuleaux triangle (found in rotary engines) and a Reuleaux pentagon- note how the two straightedge rulers remain parallel as the shapes rotate between them, just as one would expect circles to behave! These physical representations of the special curves seen here are produced by Maths Gear (Matt Parker and Steve Mould).
Airplane Glory
Wikipedia has this introduction to the phenomena of the Aircraft Glory
For a detailed discussion with math, see this entry from the Physics Stack Exchange
Airplane Glory: optical phenomenon that forms rings of color in the clouds- in this case around the shadow of my 737 flight, and is not the same physical process as that of a rainbow. Airplane glories are produce only by very tiny droplets (tens of visible light wavelengths across) in the cloud, and arise due to complex process called wave tunneling, where the electromagnetic waves that make the colors are induced in the drop by a photon only passing close by its surface. Interestingly, the exact details of this phenomenon is still an active area of research! Caught this out the window returning yesterday from a national science teachers convention in Atlanta.
Reflection Symmetry Sculpture
This sculpture and others available here:
From Etsy: BUY NOW Steinbach Reflection Scupltures
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Reflection Symmetry Sculpture: precision etched into one side of a triangular prism, multiple reflections within the optical grade glass create the 3D castle and grounds. Fun use of symmetry and geometry in this optical crystal sculpture series by Steinbach.
Trihexaflexagon
Print and construct one from templates available here:
From Puzzles.com: Flexagon Templates
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Trihexaflexagon: folded and glued out of a strip of paper this object has six distinct sides made from three sets of triangle panels. G4G week- Discovered in 1939 by mathematician Author Stone and developed along with fellow Princeton student Richard Feynman and others, but made popular by Martin Gardner.
Catenary Arch
Catenary Curves at the Exploratorium.
Visit the Exploratorium
Paul Hewitt wonderfully describes the physics of the catenary.
Catenary Arch @exploratorium : when an arch is built in the shape of this special mathematical curve (even with slippery blocks) the compression forces between each block are always parallel to the curve- the stack is stable with no tendency to buckle. The catenary is the exact shape of a chain hanging by its ends, also known as the hyperbolic cosine. Famously used in architecture, from the buttresses of Notre Dame to the Gateway Arch. ?With special thanks to the Exploratorium!
Catenary Curve
Get scale models here:
From Amazon: BUY NOW Scale Gateway Arch
Learn about the sunshield of the James Webb Space Telescope here:
SmarterEveryDay: Episode 270: JWST Sunshield
Click this link for more catenary curve fun!
Catenary Curve: What do the James Webb Space Telescope and the Gateway Arch have in common? The 5 sunshield panels of the JWST are engineered to be pulled into shape by the geometry of the catenary curve (see the latest video from SmarterEveryDay for amazing details on this). The Gateway arch is perhaps the most iconic use of this engineering principle and it matches the shape of a chain hanging from two ends, a curve known as the catenary or hyperbolic cosine- demonstrated here with a scale model souvenir (1”=100’). When an arch is built in the shape of this special mathematical curve the compression forces between each segment are always parallel to the curve- the arch is stable with no tendency to buckle. Famously used in design from the buttresses of Notre Dame to the Gateway Arch, and now in orbit about the Earth-Sun L2 point!
Bimetallic Jumping Disks
Get a set here!
From Grand Illusions: BUY NOW Bimetallic Jumping Disks
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Bimetallic Jumping Disks: (wait for it!) slightly bowl shaped disks comprised of two thin fused sheets of different metals- each with a different coefficient of thermal expansion. If the disks are warmed to body temperature they will stay buckled if pressed- when they cool, they spring back into their original form with a sharp snap. Watch with sound on.
Bismuth Diamagnetic Trap Levitation
See more of Ernie's amazing creations here in his Etsy shop Element83
From Etsy: BUY NOW Magnetic Levitation Sculptures
From Etsy: BUY NOW: Bismuth Maglev Rod
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Bismuth Diamagnetic Trap Levitation: neodymium cube magnet trapped between two pieces of strongly diamagnetic bismuth crystal. Diamagnetic substances only have magnetic fields of their own when placed in an external magnetic field from another source- here the cube shaped magnet supplies the field. Diamagnetic fields are pretty weak though so two large ceramic magnets are placed on each side and adjusted to help lift the cube magnet against gravity. Trapped in equilibrium by these magnetic fields, the slightest air currents can send the cube magnet dancing. Swipe to see a vertical trap based on the same physics. More amazing creations by Ernie McElhannon.
Peridotite Xenoliths
samples available here:
From Etsy: BUY NOW Mantle Xenolith Peridotite sample
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Peridotite Xenoliths: here before you are chunks of Earth's mantle material from 50 kilometers or deeper below the surface, far below the deepest hole ever drilled at 12.3 km (a great effort which didn't even break through to the mantle). However, green peridotite crystals of olivine and pyroxenes are sometimes brought to the surface by viscous lava in the form of xenoliths- inclusions in the volcanic basalt as seen in this sample. This piece was collected from Peridot Mesa in the San Carlos Volcanic Field of AZ. Amazing sample of the inaccessible Earth's interior.
Tessellating Geckos
Laser cut geckos are available here:
From Etsy: BUY NOW Tessellating Geckos
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Tessellating Geckos: MC Escher inspired lizard cutouts interlock precisely to tile a surface with no overlaps or gaps. Laser cut from maple, walnut, and cherry wood by maker/artist Craig Caesar and inspired by MC Escher’s “Study of Regular Division of a Plane with Reptiles” 1939. G4G week: Martin Gardner wrote about the art and math of Escher in 1961- which helped create the popularity that his work has experienced ever since.
Computational Caustic Projection
Exclusive offer: get this limited edition sample of this new artform here:
From STEMcell Science: BUY NOW: Caustic Projection Lion
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Computational Caustic Projection: an image is formed by refraction through a free form lens in a new process that utilizes the physics behind how light is concentrated into caustics. This piece of molded acrylic has a surface of slight but precisely constructed curves, that when lighted by a broadband light source (Maglite flashlight bulb), projects an image of a lion onto a plane. This is not a hologram, but instead a new proprietary light redirection technology by the company RAYFORM. Special thanks to @rayform technologies for sending me this sample.
Tesla’s Egg of Columbus
PhiTOPs are available in Aluminum and Brass:
From Etsy: BUY NOW PhiTOP in Brass
From EI: BUY NOW PhiTOP in Aluminum
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Click here for more on the PhiTOP and using magnetic induction to spin it up.
Tesla’s Egg of Columbus: a copper ellipsoid egg (PhiTOP) mysteriously spins and stands upright in this modern version of Tesla’s famous demonstration from the 1893 World’s Fair in Chicago that first showcased the principles behind wireless power transfer and his AC induction motor. Rotating magnetic fields from under the wooden platform induce electric eddy currents to flow in the copper PhiTOP- these currents then create their own magnetic field which oppose the initial fields underneath and pushes the PhiTOP to spin. This version differs from Tesla’s in that the rotating magnetic fields are created by, well, a pair of rotating neodymium magnets (revealed by lifting the top platform in this model). Credit to astrophysicist Kenneth Brecher, the creator of the PhiTOP, and this unique means of using a common lab magnetic stirrer to create the induced currents. Finally, the ellipsoid top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top.