Some examples of O'Grady's vortex marbles are available on eBay:
From eBay: BUY NOW Vortex Marbles by Kevin O'Grady
A number of artists now offer vortex marble art on Etsy
From Etsy: BUY NOW Vortex Marbles
Vortex Marble: glass art intersects with the physics of optics in this lampwork art form invented by Kevin O’Grady circa 1994- and this marble bears his signature mark on the back. The clear glass face on these marbles acts as a convex lens giving the illusion that the spiral goes deeper than the diameter of the marble. Different kinds of dichroic glass (doped with thin layers of metals and oxides) is mixed in to the borosilicate marble to create the intense colors.
Get this version here:
From Grand Illusions Ltd: Dudeney's Dissection
Dudeney's Dissection: an equilateral triangle can be cut (dissected) into four pieces that will then assemble into a square. Interestingly the four parts are all different in shape (the green and yellow pieces are similar but not the same). This hinged model is comprised of precision machined and anodized aluminum, and can be folded back and forth between the two simplest regular polygons. It is not known if a similar three piece dissection is possible. Also called the haberdasher's problem and described in 1907 by Henry Dudeney it is the only 4 piece solution known.
Choose your color and get one here:
From Etsy: BUY NOW
Hyperboloid Pencil Holder
don't forget a set of pencils:
From Amazon: BUY NOW
Colored Pencil Sets
Better yet- get some thermochromic color changing pencils!
From Educational Innovations: BUY NOW
Pencil Hyperboloid: a perfect gift for any math teacher- the precisely oriented holes in this base direct 16 pencils to reveal a hyperboloid, the 3D surface traced by revolving a diagonal(skew) line, the outline of which is the conic section of the hyperbola. A doubly ruled surface for any desktop!
Another wonderful desing by BinDesign- get one here in black or natural wood:
From Etsy: BUY NOW: Bin Design Balancer Puzzle
Balance Stacking Sculpture: a series of torques in unstable equilibrium complete this Calder-esque structure. As each component is added its weighted end balances all the others before it, with the initial small piece weighing about a gram or so. Remove the end piece and the whole structure comes down. Another wonderful design by artist Bin Xu.
The book by mathematician Solomon Golomb that started the polyonomo recreational math craze:
From Amazon: BUY NOW: Polyominoes
Pentominoes: The 12 possible arrangements of five identical squares joined edge to edge. Since 5x12=60, the pentominoes can tile a 6 x 10 rectangle with no gaps (2339 ways to do this- yet even finding one solution is a challenge). I love this beautiful set from artist/woodworker Ron Moore where each pentomino is made from a different kind of hard wood.
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.
Very nice wooden mini-teleidoscopes are affordably priced here:
From Amazon: BUY NOW Mini Teleidoscope
From Etsy: BUY NOW Mini Teleidoscope
Diffraction spin disks are getting harder to find. Here are some sources:
From eBay: BUY NOW Diffraction Spin Disk
and here: From Flynn Sci: BUY NOW Atom Disk
Teleidoscope with Reflective Diffraction Disk: a teleidoscope is like a kaleidoscope but with a lens on the end, such that the kaleidoscopic image is formed by whatever is put in front of it. Here a well crafted wooden teleidoscope is directed towards a spinning sheet metal disk with patterns of reflective diffraction gratings- seen here under a 40 watt incandescent bulb.
This plasma mug was sold in the 1990s but can be found on eBay often:
From eBay: BUY NOW: Plasma Mug
An improved and beautiful version sold here:
From Etsy: BUY NOW: Plasma Mug
Tesla’s Plasma Mug: this double walled glass mug glows orange from the excitation spectrum of neon gas at low pressure. The base contains a high frequency transformer that generates high voltage electric fields (but at very low current) from 8 AA batteries- which excites the neon to glow, and also serves as a coaster. This crazy item was produced by Can You Imagine Toys in the 1990s- perhaps Tesla himself would have served a good beer in this mug!
Get this "impossible" jar and other amazing things from this shop:
From Etsy: BUY NOW: Impossible Jar & Golf Ball
Impossible Jar with Golf Ball: a regular off the shelf golf ball somehow trapped within a standard glass jar. Neither the ball nor the jar were cut or glued in the fabrication process. The puzzle aspect is to consider how this object was produced (again, I have some theories- but I do not know the secrets of this artist). This incredible piece was made by craftsman and artist Nathan Nickerson, and comes with the golf tee display stand (a nice touch!)
This set of 3D printed scutoids available here:
From Etsy: BUY NOW: Scutoid container set
Scutoids: a recently recognized form of geometric solids discovered in 2018. Scutoids have a different polygon on each end, and when packed together maximize stability and minimize energy when forming a boundary layer- such as the membranes around organs in living tissue. These 5-6 scutoids have pentagons on one end and hexagons on the other. Discovered by a collaboration of biologists and mathematicians in 2018, this set is sold by Recep Mutlu of 3DPrintBase.
Get this 3D printed top here:
From Etsy: BUY NOW: Orbit Spinning Top
Orbit Spinning Top: asymmetric in shape but perfectly balanced about the rotation axis, this beautiful stainless steel 3D printed top will spin for a couple minutes. As the top slows down interesting aliasing arises as the angular velocity changes with respect to the frame rate of the camera.
This bird-in-egg and similar vintage style tin toys avalable here:
From eBay: BUY NOW: Centripetal Egg Tin Toy
From Etsy: BUY NOW: Centripetal Egg Tin Toy
Centripetal Egg: a simple rack and pinion mechanism spins up the tin egg shell to reveal a duckling in this vintage style tin toy. The four pieces of the egg shell are held in place with a rubber band. With sufficient centripetal acceleration the elastic force of the rubber band is temporarily overcome until the spinning assembly slows down and the egg snaps shut again.
PhiTOPs are available in Aluminum, Brass, and Copper (most conductive!):
From Etsy: BUY NOW PhiTOP in Copper
From Etsy: BUY NOW PhiTOP in Brass
From EI: BUY NOW PhiTOP in Aluminum
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.
Get similar beadwork geometric art here:
From Etsy: BUY NOW: Beadwork Kaleidocycle
Beaded Kaleidocycle: based on a geometry of six linked tetrahedra with hinged connections that allow the ring to be rotated through its center. Intricate beadwork meets math in this kinetic artwork by Erin Peña.
Avalable in five colors! Get one here:
From Mr. Sci (Science Factory): Rheoscopic Planet
Rheoscopic Planet: this example of fluid flow kinetic art uses rheoscopic fluid encased in flexible bubble of plastic to reveal the intricate motion of turbulence. A suspension of tiny flat mica crystals tend to align themselves at the boundaries where the fluid is moving comparatively faster or slower, making the typically invisible flow patterns visible. Another unique science toy from @mrscisciencefactory
These fountains are individually made by the artist hence they are priced as art reflecting the labor involved:
From Etsy store of Stephen Co : BUY NOW
Aquarius Fountain Lamp
Aquarius Fountain Lamp: an oscillating stream of water is illuminated by strobe lights to reveal underlying structures and forms typically hidden from our vision. With the help of programmable micro-controllers, strips of addressable RBG LEDs are made to flash in sequences that make the water stream appear to move upwards, change colors, and split into multiple braided streams. Art meets physics and clever technology in this wonderful creation by computer engineer Stephen Co. With sincere appreciation to Stephen @northerncircuits for sending me one of his hand crafted high tech fountains.
Get this precision machined and balanced desk pendulum here:
From Etsy: BUY NOW Double Chaotic Pendulum
Mini Double Pendulum: the intricate dance of 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. Chaotic motion (shown here in 240 fps slow motion) is characterized by extreme sensitivity to initial starting conditions, tiny differences in how the system is released leads to dramatically different outcomes each time. This well made precision bearing double pendulum is made by Doug Cvelbar.