### Tesla's Egg of Columbus Replica

Get an amazing reproduction here:

From engineDIY: **BUY NOW: Tesla's Egg of Columbus**

*Note: this site contains affiliate links for which I may be compensated*

Get an aluminum phiTOP "egg" here: **BUY NOW phiTOP **

Tesla’s Egg of Columbus Replica: an egg of brass mysteriously spins and stands upright in this museum quality replica 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. The base has no moving parts- instead special copper windings (very similar to Tesla’s original design) form four electromagnet coils on a circular steel core, and a special circuit supplies each with AC currents in such a way that a rotating magnetic field is created. This rotating magnetic field from the coils under the concave glass induces electric eddy currents to flow in the metallic brass egg. These currents within the conducting metal of the egg then create their own magnetic field, which by Lenz’s law oppose the initial fields underneath and pushes the egg to spin. Finally, the oblong egg stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top. Flipping the switch reverses the rotation direction induced by the coils.

### The Magic Octagon Coin

Get this new amazing coin here:

From Shire Post Mint: **BUY NOW: Magic Octagon Coin**

*Note: this site contains affiliate links for which I may be compensated*

“Magic Octagon” Challenge: introducing a beautiful copper coin version of this puzzle of successive rotations. Which way will the light arrow point after left and right rotations of the dark arrow? No trickery here- just the math of geometry, symmetry, rotations, and reflections and how our intuitions often fail us upon first attempts. Swipe twice for second challenge. In collaboration with my friends at @shirepostmint

### 1 mole Carbon Block

Avialable exclusively from:

STEMCell Science Shop: **BUY NOW: 1 mole Carbon Block**

*Note: this site contains affiliate links for which I may be compensated*

1 mole Carbon Block: by Avogadro’s famous number there are 6.022×10^23 atoms contained within a mole of substance- a very large number because atoms are very tiny. This chunk of graphite is precisely cut to weigh 12.011 grams, and hence when you pick it up you will have, in your hand, 6.022×10^23 Carbon atoms (to better than 1 part per thousand). That’s 602.2 billion, times a trillion, atoms! Such numbers are a challenge to conceptualize, so in collaboration with STEMCell Science Shop we introduce our specially cut and engraved “1 mole of Carbon Block”— to put an Avogadro’s Number of atoms on your shelf.

You might also like: our **Earth Mass Blackhole Replica**

### Square Dissection Puzzles

Get these and other well made disection puzzles here:

From Etsy: **BUY NOW: Square Dissection Puzzles**

These puzzles are expertly laser cut and sold by GamesEfce. I spray-painted the pieces of mine to better show the shapes and relationships for the video.

*Note: this site contains affiliate links for which I may be compensated*

Square Dissection Puzzles: a square can be cut (dissected) into polygons and then reassembled into other regular polygons. Shown here: an equilateral triangle, a pentagon, and a hexagon. These are the record holders for smallest number of pieces needed: triangle (4 pieces by Henry Dudeney 1902), hexagon (5 pieces Paul Busschop 1870s) and pentagon (6 pieces Robert Brodie 1891). Fun fact- It is not known if any of these records are the smallest possible, no mathematical proofs yet exist on this question.

### Buda Ball

Only made by the Flyte team:

From Art of Play: **Buda Ball**

*Note: this site contains affiliate links for which I may be compensated*

Buda Ball: my favorite powered levitation device- and the only system I know of that will suspend in a horizontal direction as seen in this video. A spherical magnet is pinned 1.5 centimeters from the surface of its hardwood base. Within the base is an innovative control system with adjustable electromagnet coils in a feedback loop with Hall effect sensors (I assume) which allow for fine tuning of a magnetic field to precisely balance the pull of gravity- even when the base is in a vertical orientation!

### Galton Boards: Small and Large

Available here:

From Amazon: **BUY NOW: Desk Galton Board **

From Amazon: **BUY NOW: Display Galton Board** (comes with an wonderful fact filled booklet).

*Note: this site contains affiliate links for which I may be compensated*

Galton Boards Large & Small: 6000 steel balls vs. 3000 in the compact version. Each ball has a 50/50 chance of going left or right at each branch such that the balls are distributed at the bottom by the mathematical binomial distribution (12 layers for the desk version, 14 layers for the deluxe). In addition the number of balls in each bin can be predicted by Pascal’s triangle, where the number on each hexagonal branch point represents the number of possible paths to reach that point from the top. Two extraordinary designs by Philip Poissant and the best version of the Galton Board since its invention by Sir Francis Galton(1894). An amazing demonstration of the Central Limit Theorem for the home or classroom!

### Doubly Impossible Bottle

Each constructed by hand, each a work of art- get a personalized bottle here:

From The Bottleologist website: **BUY NOW: Impossible Bottle with Frame**

From his Etsy store:** BUY NOW: Impossible Bottles**

*Note: this site contains affiliate links for which I may be compensated*

Doubly Impossible Bottle: the newest seemingly impossible object in my collection from craftsman/artist Grant Wicks @thebottleologist. An “impossible nail” object was somehow assembled within a Fannys Bay Whisky bottle- and personalized with my logo too! The puzzle aspect is to consider how the bottle was produced (I personally have some theories- but I do not know the secrets of this artist). I can tell you with high certainty that the bottle was never cut or altered in anyway, and it was not somehow formed around the objects inside.

### Perpetual Motion Simulator Marble Machine

Available here:

From Etsy: **BUY NOW: Perpetual Marble Machine **(reccomended seller: William Le of BackToNatureDecor)

*Note: this site contains affiliate links for which I may be compensated*

Note: poorly designed knock-offs are being sold widely that are not at all the same device. If the price is less than $100 USD then it is not the same quality device and mechanism as shown here.

Perpetual Motion Simulator: this marble machine device does not break any laws of thermodynamics- but it sure looks like it! When I first saw videos of this piece of kinetic art I thought the effect was due to video editing, but in fact the base contains a power source and very clever mechanism (swipe twice for clue/partial reveal). An amazing piece of art by William Le expertly crafted from stainless steel wire, doussie hardwood, and undisclosed internal components.

See Steve Mould's excellent video for details on the Perpetual Motion Simulator Circuirtry

### Perpetual Motion Simulator V2.0

This new demonstration transparent model is available here:

From Amazon: **BUY NOW: Transparent Perpetual Simulator**

Get the original here:

From Etsy: **BUY NOW: Perpetual Marble Machine **(reccomended seller: William Le of BackToNatureDecor)

*Note: this site contains affiliate links for which I may be compensated*

Perpetual Motion Simulator V2.0: a version with a transparent casing that reveals the sophisticated mechanism and electronics behind the newest “perpetual motion” toy that hit the internet a couple years ago. The original version was expertly crafted to make the base look like a block of wood (see post from November), but here we see a battery, a coil, a set of large capacitors, and a blue sensor unit along with circuit boards. The sensor detects the descending metal ball and then in an amazingly short amount of time the circuit discharges the capacitors through the coil to produce a magnetic pulse that accelerates the ball. Still looking into what kind of sensor is used- but this circuit is an excellent reminder that when someone claims a perpetual motion device the question to ask is “where’s the battery hidden?”

See Steve Mould's excellent video for details on the Perpetual Motion Simulator Circuirtry

### Chaotic Double Pendulum with Ring

Availalble here:

From Grand Illusions Ltd.: **BUY NOW: Chaotic Pendulum Kit**

*Note: this site contains affiliate links for which I may be compensated*

Chaotic Double Pendulum with Ring: 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 back and forth between the potential energy of gravity to the kinetic energy of motion. Chaotic 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. Another extraordinary design by Kontax Engineering Ltd.

### Magic Portal Illusion

Get one, expertly printed and assembled, here:

From Etsy: **BUY NOW: Magic Portal Illusion Desk Toy**

Or print it yourself: **3D Print Files: Magic Portal Desk Toy**

*Note: this site contains affiliate links for which I may be compensated*

Magic Portal Illusion: this astonishing design utilizes the famous barber pole illusion to make it appear as though these colorful strands are passing in and out of a 4th dimension. The mechanical principle employed is similar to that of a lead screw and slider type actuator, except here translating the slider up and down rotates the helical strands at just the right rate to produce the illusion. An amazing 3D print creation of Ada Cohen, printed and assembled by Alex L. Kling.

### UFO Mirascope

Similar devices available here:

From Educational Innovations: **BUY NOW Mirascope **

From Amazon:** BUY NOW Mirascope **

Alien version** available here**

*Note: this site contains affiliate links for which I may be compensated*

UFO Mirascope: two parabolic mirrors create a 3D image above the actual object. The image of the tiny alien made here is not a hologram and is produced solely by reflection of light rays between special concave mirrors. Love the space saucer theme on this version. The mirascope design principle was discovered circa 1969 by Landry and Elings at UC Santa Barbara.

### Hyperbolic Holes

This inexpensive kit available here:

From Amazon: ** BUY NOW: Hyperbolic Holes Kit**

*Note: this site contains affiliate links for which I may be compensated*** **

Hyperbolic Holes: a straight rod, in this case a pencil, glides through a symmetrical pair of curved holes. The design is based on the hyperboloid, the 3D ruled surface traced by an offset rotating diagonal line. This device is sold as an inexpensive kit to assemble yourself, and includes a motor with geared drive and pre-cut pieces. The pencil is my addition- sharpened to just the right size to clear the curved openings.

### Simple Stirling Engine

Get this amazing model engine here:

From EngineDIY: **BUY NOW: Simple Stilring Engine**

See other featured DYI devices here: **EngineDIY Models**

*Note: this site contains affiliate links for which I may be compensated*

Simple Stirling Engine: Perhaps the simplest piston engine ever devised- a single piston powered by a tiny alcohol lamp. Glass components allow a view of the internal workings of this design, and the interesting startup behavior from oscillation to full rotation. Heat engines produce mechanical motion from a difference in temperature- here the piston side is near room temperature (the central aluminum post is an excellent conductor and acts as a heat sink as the gas flows through), and the test tube is kept at high temperature via the flame, with metal fibers to help conduct the heat into the air (this component is called the regenerator). Swipe to see the elegant assembly of this model, and swipe again to see the engine power down. This external combustion design is attributed to Scottish engineer Robert Stirling back in 1816.

### Arrow on Mobius Strip

Get this fun demostration printed here:

From Etsy: **BUY NOW: Mobius Strip with Arrow**

Get the 3D print stl files here:

From printables: **download now: Mobius Strip with Arrow**

*Note: this site contains affiliate links for which I may be compensated*

Arrow on Möbius Strip: on the geometry of a Möbius strip a right pointing arrow points left after one trip around, a second trip restores the original orientation. This mathematical property is called non-orientability, and is also true of Klein bottles which I’ve posted about. I love how this 3D printed model, designed and produced by Wes Pegden, allows one to physically manipulate and intuit this somewhat obscure mathematical property.

### Feel Flux Loop

Available as a set, or individually (all come with the super powerful sphere magnet) here:

From feelflux.com:** BUY NOW**: **Copper + Aluminum Feel Flux**

See my other posts on the Feel Flux devices

*Note: this site contains affiliate links for which I may be compensated*

Feel Flux Loop: original (copper) and the "Skill Flux" version (aluminum)- toys that use Lenz's Law to manipulate a very strong neodymium magnet. A changing magnetic field (such as that from a falling magnet) induces an electric current in the copper, which in turn produce an electromagnetic field (but of lesser strength) with opposing polarity. Interestingly the magnet falls a bit faster through the aluminum even though the walls are thicker- Al is only about 60% as conductive as Cu- so it takes more material to induce the needed magnetic field using aluminum. Interestingly the Al tube is about half the mass of the Cu one, even though it is larger in volume.

### Rhythmic Ferrofluid

Get this affordable ferrofluid device here:

From Etsy:** BUY NOW: Iridescent Ferrofluid**

*Note: this site contains affiliate links for which I may be compensated*

Rhythmic Ferrofluid: an iridescent magnetic fluid interacts with a variable strength electromagnet (like those found in speakers). A circuit supplies power to the electromagnet in proportion to the sound waves picked up by a microphone, the changing magnetic field- combined with the liquid surface tension of the colloidal ferromagnetic liquid- produces the captivating motion that keeps time with any music played.

### Klein Bottle

Get this mathematical glass art here:

From Etsy: **BUY NOW: Klein Bottle**

*Note: this site contains affiliate links for which I may be compensated*

Wikipedia has great details on the Klein Bottle

Klein Bottle: 3D representation of a four dimensional mathematical object with one side, no edges, and zero volume. Kind of like a MoĢbius strip with no edges.* Math meets glass art with this fun “lamp shaped” version! *only achievable in 4D space