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Physics Toy Store 09


String Hyperboloid at the Exploratorium

String Hyperboloid @exploratorium : 26 strings held straight by hanging weights can be rotated as a set to produce a hyperboliod- the quadric surface related to the revolution of hyperbola around its axis of symmetry. Note that although this 3D shape is curved, an a infinite set of straight lines (like those of the strings) lie on its surface. Turning the top disk of this exhibit raises the weights on each string so that when it is released the potential energy will transfer back and forth to kinetic energy of rotation until the energy is damped out due to friction. 🌟 With thanks to the Exploratorium! ➡️ Follow the link in my profile for more info and where to get many of the amazing items featured here on @physicsfun #math #mathtoy #mathstoy #geometry #physics #physicstoy #hyperbola #hyperboloid #conicsection #ruledsurface #hypnogizmo #science #exploratorium #scienceisawesome

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Visit the Exploratorium
See next video for a fun toy based on the same geometrical object:


Hyperboloid Spinner
Now available here-- fully assembled or as a kit:

From Amazon: BUY NOW Hyperboliod Spinner: The HypnoGizmo


Tessellating Geckos

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. ➡️ Follow the link in my profile for info on where to get this and many amazing math and science toys featured here on @physicsfun #tesselation #tessellations #MCEscher #Escher #math #physicstoy #mathtoy #mathstoy #maths #gecko #puzzle #interlocking #tiling #martingardner #G4G #scienceisawesome

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These laser cut hardwood geckos are available here:

From Etsy: BUY NOW Tessellating Geckos


Cylinder Anamorphic Art

Mirror Anamorphosis: this famous print by artist István Orosz has a hidden anamorphic image revealed by placing a mirrored cylinder over the depiction of the moon in the image. The work visualizes a scene from the book “The Mysterious Island” by the science-fiction author Jules Verne- whose portrait emerges in the reflection on the cylinder. The math describing this mapping is quite complex and was given in detail in a physics journal in 2000, but before that Martin Gardner described the math in 1975. Repost for this week’s theme as I head to G4G! ➡️ To learn more and to find out where to get this poster please follow the link in my @physicsfun profile. #math #mathtoy #anamorphos #art #physics #physicstoy #mirror #cylinder #Orosz #IstvanOrosz #science #anamorphic #anamorphicart #scienceisawesome #anamorphosis #JulesVerne #martingardner #G4G #cylindrical #perspective #mirrorAnamorphosis #mathstoy #geometricprojection

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This image by István Orosz is available as a poster and as a puzzle:

From Amazon: BUY NOW Mysterious Island Puzzle
From MathArtFun.com: BUY NOW Mysterious Island Poster
For those who want to see the math behind this art, here is an initial paper on the topic published in 2000 in the American Journal of Physics: Anamorphic Images by Hunt et al.
Many books are available (with mirror cylinders) from Amazon: Anamorphic Art in Books


Libyan Desert Glass

Libyan Desert Glass: mysterious ancient natural glass found throughout the Sahara desert of Egypt and Libya. Current best hypothesis is that the glass was created by a very large meteor that exploded in the atmosphere with so much energy that the earth underneath the blast melted into glass. The glass formation happened about 26 million years ago, but a scientific consensus on how exactly this happened has not been achieved. ➡️ Follow the link in my profile for info on where to get this and many of the amazing items featured here on @physicsfun #physics #geophysics #physicstoy #geophysicstoy #rockhound #glass #libyandesertglass #Sahara #desertglass #tektite #impactite #naturalglass #meteor #airburst #astrophysics #meteorite #science #scienceisawesome

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Get a sample of desert glass here:

From eBay: BUY NOW Desert Glass Specimen
Get the nice display stand here:

From eBay: BUY NOW Caliper Display Stand

Circularly Polarized Reflecting Scarab

Circularly Polarized Reflecting Scarab: the iridescent jewel scarabs like this one (Chrysina Gloriosa) have a very rare property: they reflect only circularly polarized light! When viewed through a filter that allows only left CP light the metallic greens and gold colors of the beetle are clearly visible, but if viewed through a right CP filter hardly any light gets through and the beetle looks dark brown. Circularly polarized light is similar to linearly polarized light except the direction of the electric field rotates around the direction of motion such that there is a left handed version (clockwise) and a right handed version. When left handed CP light reflects off a mirror it becomes right handed and vice versa- as seen here with this beetle's reflection. My CP light filters came from a pair of RealD 3D movie glasses. Nobel Laureate Albert Michelson was the first to discover that jewel scarabs preferentially reflect left CP light back in 1911. Thanks to Ken Brecher for bringing this incredible natural phenomena to my attention. ➡️ Follow the link in my profile for more info about the physics of CP light and where to get many of the amazing items (including metallic beetles) featured here on @physicsfun #polarizer #polarizedlight #circularpolarizer #circularpolarization #scarab #scarabbeetle #iridescent #iridescence #science #jewelscarab #scienceisawesome

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Specimens of this beetle are available on eBay:

From eBay: BUY NOW CP reflecting Jewel Scarab
Get the circular polarizing filters here (inexpensive):

From eBay: BUY NOW Circular Polarizing Filter Glasses
It was only recently discovered (2010) that Chrysina gloriosa and other jewel scarab beetles can actually see circularly polarized light! The metallic appearance of these beetles is a form of structural coloration involving interference.

Wikipedia has a great introduction to Circularly Polarized Light


5 Bar Telephone Magneto circa 1910

Vintage Telephone Magneto: a functioning antique 5 bar telephone magneto generator- made in 1910! As indicated by the neon bulb voltage divider- with sufficient cranking speed this generator can create more than 280 Volts AC peak to peak. The AC current is low frequency as indicated by the flickering bulbs. These generators were used to ring telephone bells up to 20 miles away, and horseshoe shaped magnets (bars) provided the induction field. ➡️ Follow the link in my profile for info on where to get a vintage magneto and other amazing things featured here on @physicsfun #telephony #AC #light #physics #magneto #telephonemagneto #physicstoy #magneticinduction #generator #alternator #voltagedivider #science #scienceisawesome

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Available here:

From eBay: BUY NOW Vintage Bar Magneto Generators




Magnetic Viewing Film

Magneview Flim: making the invisible visible and revealing the hidden physics of our everyday world. Microscopic cavities in this green film are filled with oil and tiny flakes of Nickel metal- like compass needles, the flakes align with the magnetic fields revealing the complexity of the north and south pole domains of these magnets. Two of the disk magnets have multiple north and south poles and look like gears with teeth- these are rotors from small motors. ➡️ Follow the link in my profile for info on where to get Magneview film and other amazing items featured here on @physicsfun #magnetism #magnaview #magneview #magneviewfilm #physics #physicstoy #science #magnets #Bfield #electromagnetism #magneticdomains #magneticfield #nickel #ferromagnet #neodymium #science #scienceisawesome

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Get some magnetic viewing film here:


From Educational Innovations: BUY NOW Magnetic Viewing Film


Tornado Spheres

Tornado Spheres: two ball bearings welded together can be made to spin up to 2000+ rpm by the Magnus Effect using a stream of air. Shining three colored LEDs on the spinning pair produces an illusion of floating rings along with a second illusion that these rings are rotating and changing direction due to aliasing with the frame rate of the video camera (like the famous wagon-wheel effect). ➡️ Follow the link in my profile for info on where to buy this and many other amazing items featured here on @physicsfun #spin #rpm #tornadospheres #hurricaneballs #angularmomentum #physics #physicstoy #magnus #magnuseffect #torque #rotation #rotationalinertia #amazing #concavemirror #science #aliasing #wagonwheeleffect #scienceisawesome

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Get a set here:

From eBay: BUY NOW Tornado Spheres
Get a concave mirror like the one in the video for less than $3 here:

From eBay: BUY NOW Concave Mirror
And get a set of inexpensive colored lights here:

From eBay: BUY NOW Color LED lights



Earth's Mantle: Peridotite Xenolith

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. ➡️ Follow the link in my profile for more info and how to buy a piece of the Earth's mantle material and other amazing items featured here on @physicsfun #geology #rockhound #geophysics #geophysicstoy #mantlexenolith #xenolith #physics #physicstoy #peridotite #olivine #peridot #mineral #volcanic #lava #science #scienceisawesome

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samples available here:

From eBay: BUY NOW Mantle Xenolith Peridotite sample


Bismuth Diamagnetic Levitation

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. Another amazing creation by Ernie McElhannon. ➡️ Follow the link in my profile for info on where to get this device and other amazing items featured here on @physicsfun #diamagnetism #physics #physicstoy #neodymium #magneticfield #magnetism #levitation #maglev #science #pyrolyticgraphite #scienceisawesome @element83onetsy

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See more of Ernie's amazing creations here in his Etsy shop Element83

From Etsy: BUY NOW Magnetic Levitation Sculptures


Bismuth Crystal Pendent
See more of Ernie's amazing creations here in his Etsy shop Element83

From Etsy: BUY NOW Bismuth Jewelry


Bimetallic Jumping Disks
Get a set here!


From Educational Innovations: BUY NOW Bimetallic Jumping Disks


Catenary Curve: The Gateway Arch

Catenary Curve: the Gateway Arch 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 architecture, from the buttresses of Notre Dame to the Gateway Arch. ➡️ Follow the link in my profile for more info and where to find many of the amazing items featured here on @physicsfun #exploratorium #catenary #hyperboliccosine #gatewayarch #alysiod #architecture #catenaryarch #uniformload #physics #physicstoy #science #scienceisawesome

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Get this scale model here:

From eBay: BUY NOW Scale Gateway Arch

See next video and links for more catenary curve fun!

Catenary Arch at the Exploratorium

Catenary Arch @exploratorium : when an arch is built with 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! ➡️ Follow the link in my profile for more info and where to find many of the amazing items featured here on @physicsfun #exploratorium #catenary #hyperboliccosine #gatewayarch #alysiod #architecture #catenaryarch #uniformload #physics #physicstoy #science #scienceisawesome

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Catenary Curves at the Exploratorium.

Visit the Exploratorium


Paul Hewitt wonderfully describes the physics of the catenary.


Trihexaflexagon
Print and construct one from templates available here:

From Puzzles.com: Flexagon Templates




Click here for more:

Physics Toys,



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