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Impossible Caged Golf Ball 

Some nice versions of this impossible object available here:

From Etsy: BUY NOW: Golf Ball in Wood Cage

See more of these thought puzzles in my collection here: Impossible Objects

Impossible Caged Golf Ball: Here a regular off-the-shelf golf ball somehow trapped within a cage made from a solid piece of hardwood walnut. Neither the ball nor the wood were cut or glued in the fabrication process. The puzzle aspect is to consider how this object was produced (I have some theories- but I do not know the secrets of this artist).

Ambiguous Object 

Available here: 
From eBay: BUY NOW set of four ambiguous objects with booklet 
This offical kit/book from Prof. Sugihara contains four white plastic illusion objects (including the object in the video) and a booklet. 

Some 3D prints are available from many makers here: 
From eBay: BUY NOW Ambiguous Objects 

These type of objects were invented by mathematician Kokichi Sugihara, and you can buy his other books here: 
From Amazon: BUY NOW Ambiguous Objects by Kokichi Sugihara 

Also available from Amazon (Japan): BUY NOW set of four ambiguous objects with booklet 

Another illusion design by Kokichi Sugihara of Meiji University in Japan, the inventor of this illusion and art form. A mathematically calculated combination of perspective and the physics of reflection produce this striking illusion that works in many configurations.

Impossible Bolt

Only available from these aritist/craftsmen: 

From Etsy: BUY NOW: Impossible Bolt & Nuts

Impossible Bolt: one nut threads on clockwise as normal- the other threads on counterclockwise on the same bolt! Not impossible- but carefully engineered and machined. Swipe for partial hint on mechanism. This puzzling curiosity was inverted by Scott Eliott and machined in solid brass by puzzle crafters Steve Nicholls and Ali Morris of TwoBrassMonkeys.


Hyperbolic Holes

This inexpensive kit available here: From eBay: BUY NOW
Hyperbolic Holes Kit

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- just the right size to clear the curved openings.

Magnetic Poles & Fields

Get a set here: 
From Amazon: BUY NOW Magnetic Field Viewer set 

Viewing Magnetic Poles: visualizing the invisible- tiny iron filings suspended in viscous oil gracefully chain up to reveal the presence of magnetic field lines. Can you determine how the magnetic polls are configured by the structure of the field lines? Here three configurations, initially hidden behind white foam board, create the beautiful mappings of the fields. 

Faraday Train

Here's the parts to make your own: 
From eBay: BUY NOW Neodymium Spheres 15mm 
From Amazon: BUY NOW Bare Copper Wire 10 gauge 

The wire used for the Faraday Train has to be bare- so make sure it does not have any kind of clear coating on it. The solid grounding wire sold at hardware stores works great. 

Here is a nice description of the Faraday Train and the physics of its propulsion

Faraday Train: two magnets, one battery, and a coil of bare copper wire are the simple essence of this self propelled craft. The magnets conduct electricity, thus when put in contact with the coil current will flow creating a solenoidal magnetic field in the vicinity of the battery, which in turn pushes on the magnets at each end of the battery moving the craft along. The spherical neodymium magnets used allows the craft to slide along the coil with minimal friction. 


Lenz's Law

Get a similar kit here: 
From Educational Innovations: BUY NOW Eddy Current tubes

Get some magnetic viewing film here: 
From Educational Innovations: BUY NOW Magnetic Viewing Film 

Lenz's Law: a strong neodymium magnet falls slowly down a copper bus bar as though passing through a viscous liquid. Since magnetic fields pass through copper, magneview film reveals the location of the falling dipole magnet. Moving magnetic fields from the falling magnet produce electric currents in the copper. These currents then produce magnetic fields that have the opposite polarity to the initial field. So a falling magnet makes the copper pipe briefly into an electromagnet that repels the magnet. The rectangular copper “pipe” is from a water-cooled electromagnet power supply line, 1.5 x 2 in (4 x 5 cm) in cross-section, designed to supply a steady DC current of 5000 amps. This 15” long piece weighs in at 12 lbs and has a 1/2” diameter hole for coolIng water to flow down its center. From a decommissioned particle accelerator magnet. 

Cone of Apollonius

Similar models available here:

From Amazon: BUY NOW: Cone of Apollonius

From Etsy: BUY NOW: Cone of Apollonius

Cone of Apollonius: Slicing a cone with a plane will produce the famous curves known as the conic sections, as demonstrated with this beautiful vintage wood model by Nasco. Slicing at a right angle to the cone’s axis of symmetry produces a circle, and tilting the intersecting plane a bit produces an ellipse. When the plane is tilted parallel to the side of the cone the curve produced is a parabola, and tilting even further creates a hyperbola. The discovery of the mathematics demonstrated here are attributed to Apollonius of Perga from about 250 BC- thousands of years later Kepler, Newton, and others showed these conic sections to be intricately connected to many branches of physics such as planetary orbits and the optics of telescopes.


Ring Catch Chain Trick

Get a set here: 
From eBay:(best selecton) BUY NOW Ring Chain Catch 
From Amazon: BUY NOW Ring and Chain Set 

The physics of this trick in great detail with more slow motion: Ring Falling into a Chain: No Magic — Just Physics 

Ring Catch Chain Trick: a solid ring will be caught by a loop of chain if it tumbles during its fall. By Newton's Third law, when the ring twists into and hits the chain, the impact transfers momentum to the end of the chain, which rises up and over the ring- seen here in 480 fps slow motion. 

Advanced Gyro: Hybrid Spinning Top

Get one from David Fowler's shop: 
From PhysicsHack: BUY NOW: Advanced Gyro
Made with extraordinary craftsmanship and high quality materials, and sold at a very reasonable price! 

Hybrid Gyroscope Top: the Advanced Gyro is a new design by @physicshack and in defiance of gravity this gyroscope can hang from a string attached only at one end. No pull cord needed, this unique design spins up via friction with a working surface (thin cardboard works well) and applying a circular motion to bring the rotor up to 1000s of RPM. Machined from solid stainless steel this top weighs in at about half a kilo, providing inertia that produces long spin times. 

Perspective Puzzle

Vintage puzzles in this series are sometimes available on eBay: 
From eBay: Search NOW Virtual Illusion 3D Puzzle 

Perspective Puzzle: ten flat images, when ordered and spaced correctly, combine to produce this 3D illusion of structure and depth. This vintage toy by Mattel was sold as “Virtual Illusion 3D Puzzle” where the challenge is to scramble/shuffle the 12 sheets and then place them in the correct orientation and order to complete the image. A fun application of the math and physics of anamorphosis and perspective. 


Lissajous Roller 

Available from Pyrigan & Co.

From Etsy: BUY NOW: Lissajous Roller Illusion

From ShapeWays: BUY NOW: LIssajous Roller Illusion

Lissajous Roller: when viewing this 3D printed object from the side one sees a projection of a 3:2 Lissajous curve, but the object is actually cylindrical in frame and can roll towards or away from the viewer. When in motion a “dual axis illusion” is produced where the object appears to be rotating about a vertical axis. Invented by Bill Gosper and produced by Pyrigan & Co. 

Surfs Up Wave Machine

This Simpson's themed wave machine was made back in 1999-2000 and is hard to find. Here is a fairly inexpensive wave machine that has a similar base mechanism: 
From eBay: BUY NOW Liquid Wave Machine

Surf's Up Wave Machine: Bart rides a surfboard between two immiscible liquids which are sorted under gravity by density with the densest (dyed water) on the bottom and the lightest (mineral oil) on top. Bart’s board has a density between that of the two liquids so it stays at the boundary layer, and a capsule of air above Bart’s head keeps him upright. The motorized rocking mechanism in the base is powered by one C cell battery and produces the waves at the boundary layer by sloshing and colliding the dense liquid off each end. Found this rare 1999 toy on eBay.  

Unmixing Density Column

The bottle used here is from Voss Water: a nice cylinder and the labels come off easily. Amazon has the ingedients:

From Amazon: BUY NOW 
acetoneblue glitterfood coloring, Voss Water

The density column I made for this video is based on blend of two ideas: this "science snack" from the exploratorium: Klutz-Proof Density Column and this ChemED X post: Blog of Prof. Tom Kuntzleman  

See my Salt Fractionation post for details. 

Unmixing Density Column: three liquids that won’t stay mixed! Acetone (dyed blue) floats on top of the higher density vegetable oil, which in turn floats atop salt water (dyed orange) which is more dense than oil. Acetone usually dissolves in water through hydrogen bonding interactions, but solubility can be altered. In a process called “salting out” a sufficient amount of salt is dissolved such that the water molecules, which are much more attracted to the resulting Na+ and Cl- ions (through ion-dipole bonds), will then ignore the weaker acetone hydrogen bonds. This results in the spontaneous separation of these three liquids no matter how well shaken up. 


Pendulum Clock

Affordable gravity powered pendulum clocks available here in a number of styles:

From Amazon: BUY NOW: Pendulum Clock

The version featured in the video is the: Hermle Ravensburg Clock

Gravity Powered Pendulum Clock: invented in 1656 by Christian Huygens, the physics properties of a swinging pendulum was the basis of all precision clocks until the 1940s. As noted by Galileo, the period of swing of a pendulum can be made very precise and stable depending only on its length. This modern version is made faithfully in the original design powered only by gravity as the potential energy of the descending weight is transferred to the kinetic energy of the drive train gears and pendulum. The key feature of any pendulum clock is the anchor escapement mechanism- a curved piece attached to the pendulum with two prongs that only allows the escapement wheel to move forward one tooth per swing cycle, and producing the characteristic “tick-tock” sound. The weight descends about 1 cm per hour, and when hanging from a wall the chain needs to be pulled once a week, raising the weight up about 2 m to keep the clock in operation. This beautiful clock, made by Hermle, features a chime that sounds upon the hour. 

Vibration Unthreading

Get inexpensive small motors and accesories for DIY projects here:
From Amazon: BUY NOW DC Motors Kit

A DIY project to see if just shaking a bolt at the right frequency could make a standard nut rotate and fall off. Similar physics to the phase locking propeller toy featured in my last post. Motivated by videos seen on Instagram where a brass bolt is placed in magnetic putty and the nut mysteriously rotates up and off- now convinced that vibration is how that effect is produced. Here a small DC motor spins an offset mass to produce the vibrations.

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.