Centripetal Spheres

Just thread a rubber band through two of these drilled steel balls and you are ready to go! 
From Amazon: BUY NOW: Drilled Spheres 

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Centripetal Spheres: two ball bearings connected by a rubber band orbit each other as energy oscillates between elastic potential energy and rotation kinetic energy. Just wind up the rubber band and let go. When the rubber band has unwound the rotational inertia of the bearings winds it back up until it changes direction. The process repeats until the initial energy is dissipated through friction.

Hyperbolic Holes

This inexpensive kit available here:

From Amazon: BUY NOW: Hyperbolic Holes Kit

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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.

Sucrose Crystals

Edible and pretty sugar crystal clusters available here:

From Etsy: BUY NOW: Sucrose Crystal Clusters on a Stick

and here is a fun page describing how to grow large clear sugar crystals at home.

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

Sucrose Crystals: so I recently found, in the back corner of my kitchen panty, this bottle of fancy maple syrup I bought a long time ago. Apparently the conditions in my pantry were just right to allow the sugar to form these large prismatic clear crystals. Sucrose is a complex molecule (C12H22O11) but forms crystals of elongated polyhedra often with irregular hexagonal forms as seen here. I soaked the label off this bottle to better view the crystals- and I put it back in the cupboard it to see if the crystals will grow further- accidental kitchen physics experiment in progress! 

Perpetual Motion Simulator V2.0 (reveal)

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)

The magnetic viewing film can be purchased here:
From Amazon: BUY NOW: Color Magnetic Viewing Film

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Perpetual Motion Simulator V2.0 (reveal): a follow up post using magnetic viewing film and slow motion to actually see the magnetic pulse that accelerates the ball. The sensor conveniently has a red LED indicator which flashes, and then we see the appearance of the magnetic field pulse as the circuit discharges the capacitors through the coil. The original version of this device 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. Pretty sophisticated stuff- and a great reminder that when someone claims a perpetual motion device the question to ask is “where’s the battery hidden?”

Pickagram Puzzle

Get this well made puzzle here:

From Art of Play: BUY NOW: PIckagram Puzzle

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Pickagram: an innovative update on the classic Tangram puzzle- magnets added! With pieces that cling together with a satisfying snap, the 2D puzzle formations become 3D abstract sculptures that can stand on their own. From the mind of designer and architect Gilryong Song, with inspiration from the golden ratio in its proportions and angles.

Electromagnetic Levitation Module

Get this kit here (comes complete as shown in my video):
From engineDIY: BUY NOW: Magnetic Levitation Module

The featured sculture is by Bathsheba Grossman, affordable and beautiful math art available here:
From Etsy: BUY NOW: Soliton Sculpture

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

Electromagnetic Levitation Module: this engineered control system uses adjustable electromagnets (four copper coils) and and two Hall effect magnetic field sensors (held firm embedded in white silicone) to levitate an 5cm diameter neodymium magnet platform about 3 cm in mid-air. A feedback loop informed by the Hall effect sensors allows fine tuning of the magnetic field to exactly balance the pull of gravity, and is powered by a standard USB connection. The platform also rotates, perfect for showcasing one of my metal 3D printed mathematical sculptures by Bathsheba Grossman.

Magnetic Influence on Aluminum

For this demonstration stronger magnets work best:
From Amazon: BUY NOW: Neodymium Magnets

Here is a good small turntable with bearings: 
From Amazon: BUY NOW: Spinning Base

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

Magnetic Influence on Aluminum: physics puzzler- spin a magnet under a beer can suspended by a thread, and the can will turn. Why? Aluminum is not ferromagnetic, and as shown, magnets are not attracted to the can.  So how does a spinning magnet influence the can to spin? 


Answer: the can spins due to eddy currents induced in the conducting aluminum due to the moving magnetic fields underneath. The eddy currents make the can into a temporary electromagnet that then interacts with the magnets below according to the famous law by Lenz.

Ferromagnetic Interaction

Here is the NdFeB neodymium magnet used in this video:

From Amazon: BUY NOW: Neodymium Disk Magnet

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

Please use extreme caution when handeling strong magnets like this one. Small nails, paperclips, staples and other houlshold object made with iron will interact interestingly with the magnetic field. 

Ferromagnetic Interaction: iron rich nails temporarily become dipole magnets in the presence of an intense magnetic field from a large neodymium super magnet. Here the neodymium disk magnet is set with its north pole pointing up, so the point of each nail becomes a south pole (repelling each other) and the head of each a north pole. Imbued with these temporary induced fields, the nails will try to align themselves with the neodymium dipole’s field like compass needles, and the nails will interact with each other in interesting ways.

Impossible Braid 

Get nice examples of mystery braids here:

From Etsy: BUY NOW: Impossible Braid Key Fob

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

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See other Impossible Objects in my collection. 

Mystery Braid: challenge- how can three strands be braided if both sets of ends are connected? A favorite in 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 (demonstrated here with red felt) 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! 




Natural Mineral Fluorescence 

Get ruby in matrix stones and jewelry here:
From Etsy: BUY NOW: Ruby Glow Stones

and find the sodalite bright orange fluorescent syenite here:
From Etsy: BUY NOW: Orange Glow Stones

You will also want an awesome UV flashlight like this one:
From Amazon: BUY NOW: High Power UV Light

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

Natural Mineral Fluorescence: Four mineral specimens that emit a surprising bright glow under long wave ultraviolet light (from left to right): a clear calcite crystal glows pink, a carved obelisk of grey syenite with grains of sodalite(bright orange), a carved piece of green fuchsite with red ruby inclusions(red glow) and veins of white calcite(bright white), and a polished slab of lapis lazuli with speckles of the mineral hauynite (yellow glow). The colorful glow comes from complex quantum mechanical behavior where high energy UV photons are absorbed and then lower energy photons are emitted- the physics of fluorescence.

BagleGen: Toroidal Plasma Generator 

More info here:

From TeslaCoilPro: Learn More: BagleGen and other Plasma Art

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Toroidal Plasma Generator: an intricate dance of high intensity/high frequency electric and magnetic fields produce a ring of glowing plasma within a glass sphere containing noble gasses at low pressure. This BagleGen device is the latest in high tech kinetic art by creator Zerg Dragonymous of @teslacoilpro. What most amazes me here is how these very complex fields can be produced by circuit of only a few components- the main structure in the base is a cooling fan with a huge heat sink attached to a MOSFET transistor that sits centered below the induction coil. An amazing device for the serious hobbyist!


"Impossible" Domino

Get the 3D print files here:

From Download Now: Impossible Domino

This video from The Action Lab has a good decription of rhe physics. 

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

“Impossible” Domino: a pair of specially engineered domino type objects where the right domino knocks over the left one, but then stands back up! When seen in slow motion the process becomes more clear. The main factor here is that the center of mass of the left domino is higher than that of the right one, giving it much more potential energy so when the left one topples over it can transfer some energy back to the right one. Created by the folks at viralvideolab and 3D printed by my friend Roger Key (thanks!)

Light Pipe Sculpture

Get an affordable pre-bent light pipe demo here:
From Amazon: BUY NOW: Light Pipe Demo

Make your own abstract light pipe sculpture, an inexpesive heat gun is the only needed tool:
Tool from Amazon: BUY NOW: Heat Gun

Light Pipe Sculpture: internal reflection constrains most of the laser light to propagate along the bent acrylic rod- the physics of fiber optics. This abstract sculpture was created by applying a heat gun to a 3/8” diameter acrylic rod. The laser pointer used here is blue at a wavelength of 445nm.

Rhythmic Ferrofluid

Get this affordable ferrofluid device here:

From Etsy: BUY NOW: Iridescent Ferrofluid (select option "rhythm machine")

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.