### Purple Plasma Globe

I found this Rick and Morty lamp on eBay:

From eBay: **Search Now: Rick and Morty Plasma Globe**

Similar purple globes available here:

From Amazon: **BUY NOW: Colored Plasma Globes**

Purple Plasma Globe: sold as licensed Rick and Morty merchandise this globe features a glow plasma discharge that is mostly in the violet frequencies giving this device an interesting overall purple hue (probably due to argon gas in the mix). A small high frequency coil at center of these globes creates the high voltage potential between the center electrode and the metal coated glass globe. Current then flows through the thin gas, exciting the electrons in the gas molecules, producing the colorful emission spectra that emanates from the plasma tendrils.

### 3D Print Kaleidocycle

Get this beautiful 3D Print here:

From Etsy:** BUY NOW: Kaleidocycle Fidget**

Or print it yourself: Kaleidocycle print files

3D Print Kaleidocycle: this kinetic manipulation fidget toy is comprised of six hinges such that it can twist inwards continuously. Amazingly this item is 3D “printed-in-place”, which means it comes off the printer already assembled with movable links and ensures the color gradient is continuous across the joints.

### Thermobile: Nitinol Engine

Get one here:

From Amazon: **BUY NOW**: **Nitinol Loop Heat Engine**

Thermobile: Nitinol wire loop heat engine- the memory wire straightens out when heated (contact with heat conducting brass wheel) causing the wheels to spin, providing mechanical kinetic energy from a cup of warm tea water. Swipe for a demonstration of Nitinol wire, a special alloy of nickel and titanium that can be trained to a specific shape at high temperature- bend it up at room temperature and it will snap back into shape when exposed to moderate heat such as hot tea water. This remarkable property is a type of solid state reversible phase transition known as a martensitic transformation.

### Magswitch

The smallest Magswitch in this product line, yet it can lift 17 lbs! The Magjig 60:

From Amazon:** BUY NOW Magswitch 60 **

From eBay:** BUY NOW Magswitch 60 **

Magswitch: switchable permanent magnet- a twist of a knob turns on a magnetic field strong enough to lift this 5.2 kilogram (11 pound) chunk of railroad rail. Magnetic fields, when combined, can be either additive or subtractive. This Magswitch model, the Magjig 60, works by aligning and counter-aligning two strong neodymium dipole magnets within a field channeling ferromagnetic casing.

### The HoverPen 3.0

Currenty funding thier 3rd innovative design campaign now:

From KickStarter: **Pledge Now: HoverPen 3.0 **

The HoverPen 3.0: A sleek and weighty writing pen defying gravity- at an elegant angle- trapped by a magnetic field via precision engineered placement of neodymium magnets in a space age base design.

### Interactive Logic Gate Display

Get this device here:

From Etsy: **BUY NOW: Interactive Logic Gate Display**

Interactive Logic Gate Display: the most basic four binary/Boolean logic operations that are the fundamental components of modern computers- presented here appropriately on a standard green printed circuit board (PCB) complete with the truth table for each device. These logic gates are the basic building blocks of any logic circuit, from multiplexers, arithmetic logic units, and computer memory to full microprocessors which may contain hundreds of millions of such gates on a microchip. An educational, elegant, and fun design by Tyler Jacobs.

### Disappearing Spoon

Gallimum metal and a silicone mold to produce the spoon- available here:

From Amazon:** BUY NOW: Gallium Mold Spoon Kit **

Disappearing Spoon: the metal gallium has a melting point of 30°C (86°F) and will melt quickly when exposed to tea temperature hot water- or melt in one’s hand if handled too long. This spoon was made with a silicone mold (swipe to see process), and feels and sounds just like a regular spoon, except solid gallium is brittle and the spoon can shatter like glass if dropped. An amazing parlor trick as well as a classic and historical class demonstration.

### Matsuyama's Paradox

Get this and other amazing math puzzles here:

From Etsy: **BUY NOW: Missing Square Puzzle**

Matsuyama’s Paradox: dissect a large square in to four equal quadrilaterals, rotate and reassemble- to find a small square is missing! Where did the additional area come from? Fun math involved in the design of this puzzle, which illustrates how the concept of area can often challenge our intuitions. Swipe to compare the two assemblies. A precision crafted puzzle by Jeux Efcé game shop. Wikipedia has good details: Missing square puzzle.

### Hexacon and Sphericon Rollers

Get these and other amazing developable rollers here:

From Etsy: **BUY NOW: Hexacon and Sphericon Rollers**

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.

### Impossible Braid

Get this nice example of mystery braid here:

From Art of Play:** BUY NOW: Impossible Braid Key Fob**

Here is a great video on how to make the mystery braid

See other **Impossible Objects** in my collection.

Mystery Braid: challenge- how can three strands be braided if both sets of ends are connected? (swipe for reveal) A new addition to my collection of “impossible objects”, this leather key fob is braided from a single piece of leather, constructed by making two parallel slits but not cutting the ends. The solution is well known to those in the field of leatherwork- due to a twist of topology it’s possible to make this braid if the number of left strand over right crossings equals the times the right strand crosses over the left. Four strands braided this way is not mathematically possible, but 3, 5, or any odd number can be done!

### Pentominoes 3 Color Challenge

@physicsfun exclusive design- available only from **STEMCell Science**:

From Etsy: **BUY NOW: 3 Color Pentominoes Puzzle**

Pentominoes 3 Color Challenge: fit all 12 pentominoes into a 6x10 rectangle such that no two identically colored pieces touch. Pentominoes are the set of all 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 (there are 2339 ways to do this- yet even finding one solution is quite difficult). Adding the 3 color challenge reduces the number of possible solutions to just this one shown here! Made from laser cut acrylic and wood- and now available for the first time in a limited production run.

### The Galton Board

Available here:

From Amazon: **BUY NOW **

Galton Board

The Galton Board: 3000 steel balls fall through 12 levels of branching paths and always end up matching a bell curve distribution. Each ball has a 50/50 chance of following each branch such that the balls are distributed at the bottom by the mathematical binomial distribution. One of my favorite finds of 2018! An elegantly designed modern version of the Galton Box invented by Sir Francis Galton(1894) to demonstrate the Central Limit Theorem - showing how random processes gather around the mean. In addition the number of balls in each bin can be predicted by Pascal's triangle (printed on the face over the pegs).

### The Alchemist

Bismuth levitation available here:

From Etsy- Element 83:** BUY NOW Magnetic Levitation Sculptures **

featuring amazing Bismuth Crystals, Jewelry, and Maglev Kinetic Art

Circa 1981, Physicists transmute Bismuth to Gold: Particle accelerators make possible the ancient alchemist’s dream—but at a steep cost

The Alchemist: cast from diamagnetic Bismuth, a neodymium cube magnet levitates trapped between the hands of the ancient scholar. 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 a cylindrical neodymium magnet hangs above the figure and is 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. Although alchemists never succeeded in transmuting lead to gold, in 1981 physicists used the particle accelerator at Berkeley to shoot Carbon nuclei at thin foils of Bismuth- the resulting collisions did produced a tiny amount of Gold atoms! So modern nuclear physics, applied to the element Bismuth, finally accomplished the aspirations of the alchemists. ?Another amazing creation by Ernie McElhannon.

### Euler's Disk

Get one here:

From Amazon: **BUY NOW Euler's Disk **

Wikipedia has an excellent introduction to the physics of Euler's Disk

Eulers Disk: (best with sound on) this toy exhibits the motion of a “sprolling” coin, a motion that combines spinning and rolling. Designed with a large mass and very smooth edge, this device takes close to 3 minutes to come to rest- and amazingly, the contact point between the disk and the mirror can reach a speed of more that 200 mph! This video catches the first and last parts of this 2 minute and 42 second run, with two cuts to 240fps slow motion to show the curious motion. Watch the end with the sound on!

### Metal Balance Bird

Available here:

From Amazon: **BUY NOW **

Metal Balance Bird and Stand

From eBay: **BUY NOW **

Metal Balance Bird and Stand

Metal Balance Bird: weights in the wing tips create a center of mass below the bird's beak- making a system in stable equilibrium. No magnets! This is the nicest version of this toy I’ve seen- with bird and iconic stand cast in zinc alloy metal.

### Lenticular Invisibility Sheet

This item came to me in my winter 2021 Curiosity Box subsciption:

Get (or give!) a Curiosity Box subscription here: **JOIN NOW: The Curiosity Box**

Similar lenticular sheet material avaiable here:

From Etsy: **BUY NOW: large lenticular sheets** (hide behind it!) or **small lenticular sheet material**

Lenticular Invisibility: this thin acrylic sheet is comprised of tiny cylindrical lenses which can allow images to be out of focus along one dimension which blurs thin images and hides them. This 70 lens per inch sheet is part of a lenticular optics kit that came as part of my winter Curiosity Box- amazing and fun!

### Coins of Constant Width

These triangle coins are often available on eBay.

Fron eBay: **Search NOW: Bermuda Triangle Coin**

The silver proof versions can be expansive, but sometimes the circulated coins (like those in the video) are available at a lower price.

Click to see more: **shapes of constant width**

Coins of Constant Width: this post celebrates pi day with coins in the form of Reuleaux polygons- shapes for which their perimeter/diameter = π, just like the circle! The special convex shapes of the Reuleaux triangle (Bermuda 1 dollar) and Reuleaux heptagon (UK 50 pence) will roll, because like a circle they have the same diameter from one side to the other, no matter their orientation. To demonstrate this property note how two straightedge rulers remain parallel as the coins rotate between them, just as one would expect circles to behave. Bermuda triangle (ha!) coins are the only coins produced in the shape of the Reuleaux triangle, issued in 1997-98 and featured Elizabeth II on the front and shipwrecks on the back.

### Oscilating Cylinder Steam Engine

Get this tiny working engine here: (brass and stainless steel)

From engineDIY: **BUY NOW: Tiny Steam Engine**

Two other similar mini-engines to consider: **BUY NOW: Mini-Steam 1, Mini-Steam 2 **

Oscillating Cylinder Steam Engine: a functional “wobbler” type piston steam engine complete with boiler and flywheel. In this design the cylinder and piston both rock back and forth, acting as the valve mechanism to allow the hot steam to enter through a small hole, and then exit on the next stroke out through the tiny exhaust port in the top. Takes about 4 minutes to get going after the lamp is lit. A tiny version of the invention that powered the industrial revolution.