5 Shuttle Trammel of Archimedes
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See this great video by the Mathologer for more details: Secrets of the Nothing Grinder
5 Shuttle Trammel of Archimedes: similar to yesterday’s post- but more math is revealed as extra shuttles are added. As the shuttles take turns completing their straight line journeys, the end of the crank arm traces an ellipse- and each of the five shuttle points define points on a smaller circle that rolls within the perimeter of the device. This version was crafted from fine maple, cherry, and oak by artisan Neal Olsen.
Double Pendulum Chaos
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Double Pendulum: chaotic motion from a simple assembly of two physical pendulums (one attached to the end of the other) with the energy of the system moving frenetically back and forth between the potential energy of gravity to the kinetic energy of motion. An LED light attached to the end of the pendulum allows for a good visualization of the chaotic motion- characterized by extreme sensitivity to initial starting conditions, how tiny differences in how the system is released leads to dramatically different outcomes each time.
Four Marble Puzzle
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Four Marble Puzzle: physics brain teaser- move all four marbles to their corner locations simultaneously. Each slot slopes down towards the center such that the marbles tend to stay at the center- so, how would one get them to roll outward at the same time? The solution to this puzzle (like others featured here) relies on some fun basic physics principles. Answer below and swipe to reveal solution. A beautiful and well-made puzzle from Creative Crafthouse.
Hexacon and Sphericon Rollers
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Hexacon Roller: beautiful 3D printed versions of a recent mathematical discovery of new developable rollers (objects that roll where every point on the roller’s surface comes into contact with the plane upon which it rolls). Similar to the sphericon (based on a square) the hexacon rolls in a straight line with a peculiar wobble motion but has a hexagonal cross section (swipe to see video loop of each in motion). The hexacon (2019) and sphericon (1980) are two of a family of such rollers called polycons discovered by David Hirsch, and described in a paper by Hirsch and Seaton published in 2020.
Motion of Rolling Sphericons
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Sphericons are unique solids that roll in such a way that every point on their surface comes in contact with the plane. Solids from the sphericon family all have one side and two edges. Each sphericon is based on an even sided regular polygon, with the basic sphericon derived from a square, and the next two possible shapes are the hexa-sphericon and octo-sphericon, each rolling with a more complicated path.
Chiral Aperiodic Monotile Puzzle
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Read the published paper: A chiral aperiodic monotile
Chiral Aperiodic Monotile: these puzzle pieces are all identical in shape, based on special family of forms called “specters”, and are key to a major mathematical discovery in May of 2023. Specters will tessellate a plane to infinity, similar to how squares or hexagons can tile out with no gaps. However specters are identically shaped tiles which fill the plane aperiodically- if one tries to shift a part of a specter tiling, the shifted part will not align or match up with any other part of the same tiling- all the way out to infinity! The fact that aperiodic tessellations exist at all is pretty amazing, and Sir Roger Penrose (Nobel prize in physics 2020) is also famous for discovering a pair of regularly shaped polygons in the 1970s that tile in this aperiodic way. Specters were discovered by the same team of mathematicians (Smith, Myers, Kaplan, and Goodman-Strauss) who discovered “the hat” aperiodic monotile in March 2023, but the hat needs its mirror image to complete the tiling whereas the specter does not. An amazing development found only two months after the initial major breakthrough. Credit to the @nervous.system design team for modifying the specter into an interlocking puzzle piece form- and assembling these without gaps is a fair challenge!
Bismuth Diamagnetic Trap Levitation
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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.
Tetrahedron Specular Hologram
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See other: specular holograms in my collection
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Learn more about (and how to make) specular holograms via this video by Steve Mould
Tetrahedron Specular Hologram: complex 3D images of rotating tetrahedrons arise from a surprisingly simple pattern of engraved circles. This brass disk has been machined with set of evenly spaced circles where the center of each circle falls on a triangle. The etched circular grooves reflect a point source of light as glints, and each eye sees a slightly different pattern such that, via stereopsis, the shiny points appear to float above or below the surface. Two tetrahedrons appear for each point light source used.
Zulu Telephone Wire Bowl
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Geometric Weaving: this Zulu telephone wire bowl, made in the traditions of South Africa, features a brilliant spiral pattern. The bright colors come from weaving strands of colored wires- the kind used to connect phones throughout buildings. This particular pattern inspired using a rotating base to display this bowl as kinetic sculpture.
Moire Kinetic Coasters
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Moiré Kinetic Coasters: various patterns of overlaid curved spokes rotate and produce interesting illusions of motion via moiré interference effects. Each in this set of four coasters had a clear acrylic top upon which to place your drink, with intricate laser cut wood components underneath. The set includes a frame that couples each rotating center into cogs in a kinetic art gear train. Explore constructive and deconstructive interference patterns with this practical yet fun manipulable toy.
Map of the Universe: 2dFGRS
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Map of the Universe: actual astrophysical data with 221,000 laser etched dots, each dot representing a galaxy of stars and revealing the largest scale structures of our universe. This glass cube contains a 3D mapping of galaxies using the data from the 2dF Galaxy Redshift Survey completed in 2003 which revealed the large scale clumping and voids of galaxies, the true structure of our universe out to about 2.5 billion lightyears. The 3.9 meter wide telescope took about 5 years to collect the spectra of each galaxy in two thin slices of the sky, representing about 4% of the total. The Sloan Digital Sky Survey has since expanded on this to about 40% of the sky now mapped to 12 billion lightyears. Hold and explore this mapped chunk of the universe in your own hands!
Symmetric Sticks Puzzle
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Symmetric Sticks Puzzle: 30 identical pieces, each with two notches as shown, can create 12 interlocking pentagons in a perfect symmetry- look carefully and you can see that each rod is in an identical configuration with the 4 others that connect with it. Precision notches on the rods allow them to interlock with elastic tension such that vector sum of the 4 forces sum to zero in this tensegrity type equilibrium. The dodecahedron, with its 30 edges and 12 sides, is the basis of this puzzle sculpture.
Resin Art Kalliroscope
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Resin Art Kalliroscope: visualizing fluid flow— a slight tilt of the hand speeds the bubble through the rheoscopic fluid producing a wake of turbulence made visible by the tiny flake crystals of mica catching the light. This fidget version of the kalliroscope is constructed of artistically colored and poured resin and includes a small magnet that can also be manipulated from below.
Alexandrite Effect
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Explore propperties of minerals and gemstones with this fun jeweler's flashlight:
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Alexandrite Effect: dramatic color change under different light sources- seen here first under halogen incandescent light and then under cool white LED (similar to sunlight), due to selective absorption of frequencies of visible light. These two faceted crystals are synthetic gems, Tourmalike and Tourmalike+, that dramatically exhibit this effect especially under the illumination of this jeweler’s appraisal lamp that allows one to select white light with different spectra (and also UV). This phenomenon is named for the famous (and expensive) alexandrite gemstone variety of the mineral chrysoberyl.
Phase Locking Folk Toy v5.0
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See the other versions in my collection here: Phase Locking Folk Toys
Phase Locking Folk Toy v5: a final post in this series featuring the “Magic Twin Helicopters” toy that I found in a shop at the Tokyo airport a few years back. A helicopter themed version of the hooey stick, this time with the four rotor blades serving as the propellers. Rubbing the stick over the notches creates both vertical and horizontal vibrations- and leads to a cyclic motion of the struts in the center of each of the propellers, which begin to rotate (with some effort). See previous posts for more info on this folk toy with surprisingly complex physics.
Phase Locking Folk Toy v4.0
Versions of the Gee Haw Whimmy Diddle available from these sources:
From Etsy: BUY NOW: Hooey Stick Folk Toy
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See the other versions in my collection here: Phase Locking Folk Toys
Wikipedia has some good details about the Hooey Stick toy.
Phase Locking Folk Toy v4: another interesting variation of the “hooey stick” toy in my collection. This one has two rotors both on the same stick- and often they will rotate in opposite directions! (Shown here in slow motion for clarity.) Just as with the regular version of this toy (see yesterday’s post) rubbing the stick over the notches creates vibrations- and can lead to an up and down motion of the shaft in the center of the rotors. The hole in each rotor is larger than the shaft, and when the shaft/notched stick is vibrating it only touches the rotor for a short time each cycle- if the timing is right the stick collides with the rotor such that friction gives it nudge with each vibration to set it spinning- and this can work either clockwise or counterclockwise. Sometimes they spin the same direction and sometimes opposite, which seems to depend on initial conditions and a bit of luck. This version, made in Taiwan, was sold in the 1980s.
Phase Locking Folk Toy v3.0
Versions of the Gee Haw Whimmy Diddle available from these sources:
From Etsy: BUY NOW: Hooey Stick Folk Toy
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See the other versions here: Phase Locking Folk Toys
A detailed physics analysis of this toy was published in 2018 (open acess): Physics of the mechanical toy Gee-Haw Whammy Diddle
Phase Locking Folk Toy v3: spin it left or spin it right, a slight adjustment of the hands produces different results (with a bit of practice) using this modern version of the famous Gee-Haw Wimmy Diddle folk toy. Sometimes also called a Hooey Stick as a demonstrator will often claim that calling out “Gee” makes it spin to the right, or yelling “Haw” will make it spin to the left- which of course is a bunch of hooey! Left and rightward spin shown in 240fps to reduce shutter aliasing.